On Sat, Jan 31, 2009 at 12:37:39PM -0500, Justin Piszcz wrote:

I think it was a coincidence when I tried to login before, I tried it  
again (after trying to re-produce the problem, which I had been able to  
do) and this time the mouse worked but the keyboard did not..even running
echo b > sysrq-trigger did not reboot the server..  Had to resort to  
manual method.

I am now on kernel 2.6.28.2 and will see if I can make it happen again.

This looks like the bug fixed by commit
e8c82c2e23e3527e0c9dc195e432c16784d270fa.  Make sure you have it.