I think it may be related to this bug, but I'm not sure. I took a picture of the kernel panic with my phone, and here's the (I think) interesting part of the panic:
Kernel panic - not syncing: Fatal exception in interrupt
Pid: 3003, comm: Xorg Tainted: P D W O 3.2.0-29-generic #46-Ubuntu
Call Trace:
panic occurred, switching back to text console
Does anyone know how to troubleshoot this, or add value to an existing bug report?