Hm, they might be using MythTV to cause it, too.
I had to use MythTV again today, after the computer had been running for 3 days straight with Xv working wonderfully. After using MythTV, Xv was corrupted. Had to restart X.
Note: After using MythTV and starting up mplayer the entire screen blacks out and I get an Xid error:
NVRM: Xid (0001:00): 13, 0000 01019700 00004097 00001808 00000000 00800000
Just so everyone knows, this is bug 353274.