Just wanted to save this off finally. Not that having it here will help me if I am locked up but…
If you enabled Magic SysRq (CONFIG_MAGIC_SYSRQ=y, found in make menuconfig at Kernel hacking -> Magic SysRq key) in your kernel you can cleanly reboot if evil freezes your system with the following keyboard combination:
Alt-SysRq-R (keyboard in raw mode)
Alt-SysRq-S (save unsaved data to disk)
Alt-SysRq-E (send termination signal)
Alt-SysRq-I (send kill signal)
Alt-SysRq-U (remount all mounted file systems)
Alt-SysRq-B (reboots the system)
More info at WP including some nice mnemonic’s for helping to remember.