It seems that Mozilla sunbird hangs at startup with the "Gray" theme. The following is dumped to the terminal before it hangs totally and needs to be killed:

$ ~/bin/sunbird-0.5/sunbird

***MEMORY-WARNING***: sunbird-bin[29223]: GSlice: g_thread_init() must be called before all other GLib functions; memory corruption due to late invocation of g_thread_init() has been detected; this program is likely to crash, leak or unexpectedly abort soon...
*** Calendar schema version is: 7
Starting calendar alarm service
observer added
*** glibc detected *** /home/emeitner/bin/sunbird-0.5/sunbird-bin: double free or corruption (out): 0x091fead0 ***
======= Backtrace: =========
/lib/tls/i686/cmov/libc.so.6[0xb72aa8f1]
/lib/tls/i686/cmov/libc.so.6(cfree+0x90)[0xb72adf50]
/usr/lib/libglib-2.0.so.0(g_free+0x31)[0xb77b58e1]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x823a81a]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x823b0ce]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x82397ca]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x8285dbe]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x82851d2]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x82bd675]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c462]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c52f]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c602]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c3c8]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c52f]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c602]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c3c8]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c52f]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c602]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c3c8]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c52f]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c602]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c3c8]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c52f]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c602]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c3c8]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c52f]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c602]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c3c8]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c52f]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c602]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c3c8]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c52f]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c602]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x838c3c8]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x82bacc5]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x82babe4]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x82babad]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x82a3844]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x8489fc4]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x848da4e]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x848d4a7]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x848c45c]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x848ee26]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x8489937]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x82679be]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x8260560]
/home/emeitner/bin/sunbird-0.5/sunbird-bin[0x8264df0]
/usr/lib/libgtk-x11-2.0.so.0[0xb7af8732]
/usr/lib/libgobject-2.0.so.0(g_closure_invoke+0x122)[0xb7847742]
/usr/lib/libgobject-2.0.so.0[0xb7859695]
/usr/lib/libgobject-2.0.so.0(g_signal_emit_valist+0x6d6)[0xb785a9a6]
/usr/lib/libgobject-2.0.so.0(g_signal_emit+0x29)[0xb785ad99]
/usr/lib/libgtk-x11-2.0.so.0[0xb7c31378]
/usr/lib/libgtk-x11-2.0.so.0(gtk_main_do_event+0x42f)[0xb7af1a7f]
/usr/lib/libgdk-x11-2.0.so.0[0xb792d6c1]
/usr/lib/libgdk-x11-2.0.so.0(gdk_window_process_updates+0xf5)[0xb792d805]
/usr/lib/libgdk-x11-2.0.so.0(gdk_window_process_updates+0xb2)[0xb792d7c2]
/usr/lib/libgdk-x11-2.0.so.0(gdk_window_process_updates+0xb2)[0xb792d7c2]
/usr/lib/libgdk-x11-2.0.so.0(gdk_window_process_updates+0xb2)[0xb792d7c2]
/usr/lib/libgdk-x11-2.0.so.0(gdk_window_process_updates+0xb2)[0xb792d7c2]
/usr/lib/libgdk-x11-2.0.so.0(gdk_window_process_updates+0xb2)[0xb792d7c2]
/usr/lib/libgtk-x11-2.0.so.0[0xb7c4bbc2]
/usr/lib/libgobject-2.0.so.0(g_cclosure_marshal_VOID__VOID+0x49)[0xb7855179]
======= Memory map: ========
08048000-0890d000 r-xp 00000000 08:03 3051994    /home/emeitner/bin/sunbird-0.5/sunbird-bin
0890d000-0897f000 rw-p 008c4000 08:03 3051994    /home/emeitner/bin/sunbird-0.5/sunbird-bin
0897f000-0941d000 rw-p 0897f000 00:00 0          [heap]
b2be2000-b2be6000 r-xp 00000000 08:03 2736591    /lib/tls/i686/cmov/libnss_dns-2.6.so
b2be6000-b2be8000 rw-p 00003000 08:03 2736591    /lib/tls/i686/cmov/libnss_dns-2.6.so
b2be8000-b2bea000 r-xp 00000000 08:03 2739182    /lib/libnss_mdns4_minimal.so.2
b2bea000-b2beb000 rw-p 00001000 08:03 2739182    /lib/libnss_mdns4_minimal.so.2
b2c01000-b2c05000 r-xp 00000000 08:03 4407356    /usr/lib/gtk-2.0/2.10.0/loaders/libpixbufloader-png.so
b2c05000-b2c06000 rw-p 00003000 08:03 4407356    /usr/lib/gtk-2.0/2.10.0/loaders/libpixbufloader-png.so
b2c07000-b2c08000 ---p b2c07000 00:00 0 
b2c08000-b3408000 rwxp b2c08000 00:00 0 
b3408000-b343d000 r-xp 00000000 08:03 3051935    /home/emeitner/bin/sunbird-0.5/libnssckbi.so
b343d000-b3446000 rw-p 00035000 08:03 3051935    /home/emeitner/bin/sunbird-0.5/libnssckbi.so
b3446000-b347d000 r-xp 00000000 08:03 3051931    /home/emeitner/bin/sunbird-0.5/libfreebl3.so
b347d000-b347e000 rw-p 00037000 08:03 3051931    /home/emeitner/bin/sunbird-0.5/libfreebl3.so
b347e000-b347f000 ---p b347e000 00:00 0 
b347f000-b3c7f000 rwxp b347f000 00:00 0 
b3c7f000-b3c80000 ---p b3c7f000 00:00 0 
b3c80000-b4480000 rwxp b3c80000 00:00 0 
b4480000-b4481000 ---p b4480000 00:00 0 
b4481000-b4c81000 rwxp b4481000 00:00 0 
b4c81000-b4ce1000 rw-s 00000000 00:09 5439507    /SYSV00000000 (deleted)
b4ce1000-b4ce3000 r-xp 00000000 08:03 3768597    /usr/lib/pango/1.6.0/modules/pango-basic-fc.so
b4ce3000-b4ce4000 rw-p 00001000 08:03 3768597    /usr/lib/pango/1.6.0/modules/pango-basic-fc.so
b4ce4000-b4d63000 r--p 00000000 08:03 1638437    /usr/share/fonts/truetype/ttf-dejavu/DejaVuSans.ttf
b4d63000-b4ddc000 r--p 00000000 08:03 1638418    /usr/share/fonts/truetype/ttf-dejavu/DejaVuSans-Bold.ttf
b4ddc000-b4e20000 r--p 00000000 08:03 3129766    /usr/share/fonts/truetype/msttcorefonts/Arial.ttf
b4e20000-b4e66000 r--p 00000000 08:03 3129764    /usr/share/fonts/truetype/msttcorefonts/Arial_Bold.ttf
b4e66000-b4ee5000 r--p 00000000 08:03 1638437    /usr/share/fonts/truetype/ttf-dejavu/DejaVuSans.ttf
b4ee5000-b4f08000 r--p 00000000 08:03 5915301    /usr/share/fonts/type1/gsfonts/n021003l.pfb
b4f08000-b4f0e000 r--s 00000000 08:03 3556719    /var/cache/fontconfig/945677eb7aeaf62f1d50efc3fb3ec7d8-x86.cache-2
b4f0e000-b4f0f000 r--s 00000000 08:03 3556717    /var/cache/fontconfig/fd9505950c048a77dc4b710eb6a628ed-x86.cache-2
b4f0f000-b4f12000 r--s 00000000 08:03 3556716    /var/cache/fontconfig/ddc79d3ea06a7c6ffa86ede85f3bb5df-x86.cache-2
b4f12000-b4f13000 r--s 00000000 08:03 3556710    /var/cache/fontconfig/e7071f4a29fa870f4323321c154eba04-x86.cache-2
b4f13000-b4f14000 r--s 00000000 08:03 3556707    /var/cache/fontconfig/a2ab74764b07279e7c36ddb1d302cf26-x86.cache-2
b4f14000-b4f18000 r--s 00000000 08:03 3556706    /var/cache/fontconfig/921a30a17f0be15c70ac14043cb7a739-x86.cache-2
b4f18000-b4f19000 r--s 00000000 08:03 3556705    /var/cache/fontconfig/c69f04ab05004e31a6d5e715764f16d8-x86.cache-2
b4f19000-b4f1c000 r--s 00000000 08:03 3556699    /var/cache/fontconfig/926e794c3d5e5dffcaf2fa83ef8d36c2-x86.cache-2
b4f1c000-b4f1d000 r--s 00000000 08:03 3556698    /var/cache/fontconfig/4c73fe0c47614734b17d736dbde7580a-x86.cache-2
b4f1d000-b4f1f000 r--s 00000000 08:03 3556697    /var/cache/fontconfig/646addb8444faa74ee138aa00ab0b6a0-x86.cache-2
b4f1f000-b4f21000 r--s 00000000 08:03 3556696    /var/cache/fontconfig/20bd79ad97094406f7d1b9654bfbd926-x86.cache-2
b4f21000-b4f22000 r--s 0000000/home/emeitner/bin/sunbird-0.5/run-mozilla.sh: line 131: 29223 Killed                  "$prog" ${1+"$@"}

This was Sunbird 0.5 with most required libraries bundled with it as downloaded from mozilla.org.