this while watching a movie in VLC:

Dec 13 23:06:57 stoke-buntu kernel: [23214.341275] *pde = 00000000 
Dec 13 23:06:57 stoke-buntu kernel: [23214.341290] Dumping ftrace buffer:
Dec 13 23:06:57 stoke-buntu kernel: [23214.341293]    (ftrace buffer empty)
Dec 13 23:06:57 stoke-buntu kernel: [23214.341295] Modules linked in: binfmt_misc radeon drm ppdev bridge stp bnep sbp2 lp parport joydev snd_hda_intel pcmcia snd_usb_audio snd_pcm_oss snd_mixer_oss snd_pcm snd_usb_lib snd_seq_dummy snd_seq_oss snd_seq_midi snd_seq_midi_event wlan_scan_sta snd_seq snd_rawmidi ath_rate_sample snd_timer snd_seq_device ati_agp ath_pci yenta_socket rsrc_nonstatic snd_hwdep agpgart wlan ath_hal(P) pcmcia_core snd soundcore snd_page_alloc gspca_zc3xx i2c_piix4 pcspkr psmouse video shpchp serio_raw input_polldev gspca_main output videodev v4l1_compat usbhid ohci1394 ieee1394 8139too 8139cp mii fbcon tileblit font bitblit softcursor
Dec 13 23:06:57 stoke-buntu kernel: [23214.341343] 
Dec 13 23:06:57 stoke-buntu kernel: [23214.341347] Pid: 3325, comm: Xorg Tainted: P           (2.6.28-17-generic #58-Ubuntu) Satellite A100
Dec 13 23:06:57 stoke-buntu kernel: [23214.341351] EIP: 0060:[<c049bbd0>] EFLAGS: 00013246 CPU: 0
Dec 13 23:06:57 stoke-buntu kernel: [23214.341354] EIP is at unix_stream_sendmsg+0x100/0x350
Dec 13 23:06:57 stoke-buntu kernel: [23214.341357] EAX: 00000000 EBX: f0a5ddbc ECX: 00000040 EDX: f0a5de3c
Dec 13 23:06:57 stoke-buntu kernel: [23214.341359] ESI: f350f300 EDI: f350f300 EBP: f0a5dde4 ESP: f0a5dd94
Dec 13 23:06:57 stoke-buntu kernel: [23214.341362]  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Dec 13 23:06:57 stoke-buntu kernel: [23214.341369]  f0a5dda8 f0a5de3c 00000000 f330eaec f0a5de1c f312ce00 c04285fd 00000000
Dec 13 23:06:57 stoke-buntu kernel: [23214.341535] ---[ end trace b836e76c2e669722 ]---
Dec 13 23:06:57 stoke-buntu kernel: [23214.364918] [drm] Num pipes: 2
Dec 13 23:06:59 stoke-buntu kernel: [23216.283864] [drm] Setting GART location based on new memory map
Dec 13 23:06:59 stoke-buntu kernel: [23216.284526] [drm] Loading R300 Microcode
Dec 13 23:06:59 stoke-buntu kernel: [23216.284562] [drm] Num pipes: 2
Dec 13 23:06:59 stoke-buntu kernel: [23216.284570] [drm] writeback test succeeded in 1 usecs
Dec 13 23:07:02 stoke-buntu bonobo-activation-server (ian-27350): could not associate with desktop session: Failed to connect to socket /tmp/dbus-3tqUgnY5Ml: Connection refused
Dec 13 23:07:11 stoke-buntu pulseaudio[27510]: pid.c: Stale PID file, overwriting.
Dec 13 23:07:12 stoke-buntu pulseaudio[27510]: alsa-util.c: Device hw:1 doesn't support 44100 Hz, changed to 16000 Hz.
Dec 13 23:07:12 stoke-buntu pulseaudio[27510]: alsa-util.c: Device hw:1 doesn't support 2 channels, changed to 1.

the movie stopped simultaneously with the screen blanking and I was plopped out at the GDM to log back in.

deamon.log
ec 13 22:38:58 stoke-buntu NetworkManager: <info>  (ath0): supplicant connection state:  disconnected -> associated 
Dec 13 22:38:58 stoke-buntu NetworkManager: <info>  (ath0): supplicant connection state:  associated -> completed 
Dec 13 22:47:17 stoke-buntu vlc[26514]: skins2: : skin: VLC 0.8.5 Default Skin  author: aLtgLasS
Dec 13 22:47:17 stoke-buntu vlc[26514]: logger: : using logger...
Dec 13 22:47:17 stoke-buntu vlc[26514]: skins2: : skin: VLC 0.8.5 Default Skin  author: aLtgLasS
Dec 13 23:06:57 stoke-buntu gdm[3319]: WARNING: gdm_slave_xioerror_handler: Fatal X error - Restarting :0 
Dec 13 23:06:57 stoke-buntu NetworkManager: <info>  (ath0): device state change: 8 -> 3 
Dec 13 23:06:57 stoke-buntu NetworkManager: <info>  (ath0): deactivating device (reason: 38). 
Dec 13 23:06:57 stoke-buntu NetworkManager: <info>  ath0: canceled DHCP transaction, dhcp client pid 4199 
Dec 13 23:06:57 stoke-buntu NetworkManager: <WARN>  check_one_route(): (ath0) error -34 returned from rtnl_route_del(): Sucess  
Dec 13 23:06:57 stoke-buntu avahi-daemon[3396]: Withdrawing address record for 192.168.1.100 on ath0.
Dec 13 23:06:57 stoke-buntu avahi-daemon[3396]: Leaving mDNS multicast group on interface ath0.IPv4 with address 192.168.1.100.
Dec 13 23:06:57 stoke-buntu avahi-daemon[3396]: Interface ath0.IPv4 no longer relevant for mDNS.
Dec 13 23:06:58 stoke-buntu acpid: client 3325[0:0] has disconnected 
Dec 13 23:06:58 stoke-buntu acpid: client connected from 27324[0:0] 

and I see an Oops in here kern.log:
Dec 13 23:06:57 stoke-buntu kernel: [23214.341252] BUG: unable to handle kernel NULL pointer dereference at 00000000
Dec 13 23:06:57 stoke-buntu kernel: [23214.341264] IP: [<c049bbd0>] unix_stream_sendmsg+0x100/0x350
Dec 13 23:06:57 stoke-buntu kernel: [23214.341275] *pde = 00000000 
Dec 13 23:06:57 stoke-buntu kernel: [23214.341280] Oops: 0002 [#1] SMP 
Dec 13 23:06:57 stoke-buntu kernel: [23214.341284] last sysfs file: /sys/devices/LNXSYSTM:00/device:00/PNP0C0A:00/power_supply/BAT0/charge_full
Dec 13 23:06:57 stoke-buntu kernel: [23214.341290] Dumping ftrace buffer:
Dec 13 23:06:57 stoke-buntu kernel: [23214.341293]    (ftrace buffer empty)
Dec 13 23:06:57 stoke-buntu kernel: [23214.341295] Modules linked in: binfmt_misc radeon drm ppdev bridge stp bnep sbp2 lp parport joydev snd_hda_intel pcmcia snd_usb_audio snd_pcm_oss snd_mixer_oss snd_pcm snd_usb_lib snd_seq_dummy snd_seq_oss snd_seq_midi snd_seq_midi_event wlan_scan_sta snd_seq snd_rawmidi ath_rate_sample snd_timer snd_seq_device ati_agp ath_pci yenta_socket rsrc_nonstatic snd_hwdep agpgart wlan ath_hal(P) pcmcia_core snd soundcore snd_page_alloc gspca_zc3xx i2c_piix4 pcspkr psmouse video shpchp serio_raw input_polldev gspca_main output videodev v4l1_compat usbhid ohci1394 ieee1394 8139too 8139cp mii fbcon tileblit font bitblit softcursor
Dec 13 23:06:57 stoke-buntu kernel: [23214.341343] 
Dec 13 23:06:57 stoke-buntu kernel: [23214.341347] Pid: 3325, comm: Xorg Tainted: P           (2.6.28-17-generic #58-Ubuntu) Satellite A100
Dec 13 23:06:57 stoke-buntu kernel: [23214.341351] EIP: 0060:[<c049bbd0>] EFLAGS: 00013246 CPU: 0
Dec 13 23:06:57 stoke-buntu kernel: [23214.341354] EIP is at unix_stream_sendmsg+0x100/0x350
Dec 13 23:06:57 stoke-buntu kernel: [23214.341357] EAX: 00000000 EBX: f0a5ddbc ECX: 00000040 EDX: f0a5de3c
Dec 13 23:06:57 stoke-buntu kernel: [23214.341359] ESI: f350f300 EDI: f350f300 EBP: f0a5dde4 ESP: f0a5dd94
Dec 13 23:06:57 stoke-buntu kernel: [23214.341362]  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Dec 13 23:06:57 stoke-buntu kernel: [23214.341365] Process Xorg (pid: 3325, ti=f0a5c000 task=f0e9d7f0 task.ti=f0a5c000)
Dec 13 23:06:57 stoke-buntu kernel: [23214.341367] Stack:
Dec 13 23:06:57 stoke-buntu kernel: [23214.341369]  f0a5dda8 f0a5de3c 00000000 f330eaec f0a5de1c f312ce00 c04285fd 00000000
Dec 13 23:06:57 stoke-buntu kernel: [23214.341376]  00000ee8 00000000 00000cfd 00000000 00000000 00000000 f350f300 00000000
Dec 13 23:06:57 stoke-buntu kernel: [23214.341382]  ffffffa1 c053f0a0 f0a5de3c f350f300 f0a5de04 c0422a31 00000020 c053f0a0
Dec 13 23:06:57 stoke-buntu kernel: [23214.341390] Call Trace:
Dec 13 23:06:57 stoke-buntu kernel: [23214.341392]  [<c04285fd>] ? skb_dequeue+0x4d/0x70
Dec 13 23:06:57 stoke-buntu kernel: [23214.341399]  [<c0422a31>] ? __sock_sendmsg+0x51/0x60
Dec 13 23:06:57 stoke-buntu kernel: [23214.341403]  [<c0422b1a>] ? sock_aio_write+0xda/0x130
Dec 13 23:06:57 stoke-buntu kernel: [23214.341407]  [<c01bd675>] ? do_sync_readv_writev+0xb5/0xf0
Dec 13 23:06:57 stoke-buntu kernel: [23214.341414]  [<c014ee10>] ? autoremove_wake_function+0x0/0x50
Dec 13 23:06:57 stoke-buntu kernel: [23214.341420]  [<c0287abf>] ? security_file_permission+0xf/0x20
Dec 13 23:06:57 stoke-buntu kernel: [23214.341427]  [<c01bd924>] ? rw_verify_area+0x54/0xd0
Dec 13 23:06:57 stoke-buntu kernel: [23214.341431]  [<f85202e4>] ? radeon_cp_indirect+0x1b4/0x370 [radeon]
Dec 13 23:06:57 stoke-buntu kernel: [23214.341443]  [<c01be3bc>] ? do_readv_writev+0x9c/0x1d0
Dec 13 23:06:57 stoke-buntu kernel: [23214.341447]  [<c0422a40>] ? sock_aio_write+0x0/0x130
Dec 13 23:06:57 stoke-buntu kernel: [23214.341450]  [<f851add0>] ? radeon_cp_buffers+0x0/0x1d0 [radeon]
Dec 13 23:06:57 stoke-buntu kernel: [23214.341467]  [<c05007d8>] ? unlock_kernel+0x28/0x2f
Dec 13 23:06:57 stoke-buntu kernel: [23214.341472]  [<c01ca570>] ? vfs_ioctl+0x80/0x90
Dec 13 23:06:57 stoke-buntu kernel: [23214.341476]  [<c0286429>] ? cap_capset_check+0x69/0x110
Dec 13 23:06:57 stoke-buntu kernel: [23214.341481]  [<c01be53a>] ? vfs_writev+0x4a/0x60
Dec 13 23:06:57 stoke-buntu kernel: [23214.341484]  [<c01be58d>] ? sys_writev+0x3d/0xa0
Dec 13 23:06:57 stoke-buntu kernel: [23214.341488]  [<c0103f6b>] ? sysenter_do_call+0x12/0x2f
Dec 13 23:06:57 stoke-buntu kernel: [23214.341492] Code: 74 05 e8 b4 0d f9 ff 8b 4d c0 c7 41 18 00 00 00 00 8b 7d d0 85 ff 75 06 8b 5d f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 <00> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
Dec 13 23:06:57 stoke-buntu kernel: [23214.341528] EIP: [<c049bbd0>] unix_stream_sendmsg+0x100/0x350 SS:ESP 0068:f0a5dd94
Dec 13 23:06:57 stoke-buntu kernel: [23214.341535] ---[ end trace b836e76c2e669722 ]---
Dec 13 23:06:57 stoke-buntu kernel: [23214.364918] [drm] Num pipes: 2
Dec 13 23:06:59 stoke-buntu kernel: [23216.283864] [drm] Setting GART location based on new memory map
Dec 13 23:06:59 stoke-buntu kernel: [23216.284526] [drm] Loading R300 Microcode
Dec 13 23:06:59 stoke-buntu kernel: [23216.284562] [drm] Num pipes: 2
Dec 13 23:06:59 stoke-buntu kernel: [23216.284570] [drm] writeback test succeeded in 1 usecs