Situation is like that. Many times has happened that Xorg freezes and with it also keyboard. Quite some times because of some Compiz effects or Flash (fullscreen switch). Keyboard becomes totaly unresponsive, while mouse still works (I can move cursor, but can't click since desktop freezes) and music still plays and I can connect trough ssh. This is the only way I know I can try to solve problem - either by killing browser&flash or lastly restarting xorg server.
This problem appears on more than one Ubuntu computer. My home dekstop with proprietery nvidia driver, on my work where I use noveau driever (opensource driver for geforce) and sometimes (but rarely) also on laptop with ATI graphics (using r300g driver which is really good!).
Can someone explains why mouse still works while I can't input from keyboard? (I can't switch to virtual console or do R-E-I-S-U-B command) I have USB keyboard and USB mouse.