Emergency Linux reboot:
Hit the [ Alt + SysRq ] keys together, and, holding them down, type REISUB, and you're on your way.
1. R - keyboard goes out of RAW mode.
2. E - TErminate all processes.
3. I - KIll all processes.
4. S - Sync disks.
5. U - Unmount disks and remount them read-only.
6. B - ReBoot the machine.

and

Raising Skinny Elephants Is So Utterly Boring

It happens too often with my laptop last time - smone says that trouble is serious with memory.