I too can reproduce this problem. This looks like a kernel panic to me. In X, the screen goes black except for a text cursor in the upper left-hand corner and the mouse cursor where it had last been, and the caps-lock light blinks.
If I switch to a VT, I can get nearly the same behavior, but with an error message also present:
This isn't a lot to go on, and I'm not seeing any panic information in /var/log/messages. My WAG is that intelfb means Intel framebuffer, and this panic was instigated by the video driver. But I'm way out of my league here and may be completely off base.
:~$ export DISPLAY=:0.0
** (gnome-system-monitor:1979): WARNING **: SELinux was found but is not enabled.
[ 436.144602] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: c049e1f5
[ 436.145303] [drm:intelfb_panic] *ERROR* panic occurred, switching back to text console
ETA: Sorry thomasaaron, I completely overlooked your post above. Sounds like you guys already have a pretty good idea what the problem is.