Don't rush on your decision on what's wrong.CompiledMonkey said:
Seriously, I've gotten a rash of similar issues with one of my TV's lately and it's hooked to a Verizon Motorola HD DVR box.
I think the problem is something coming through the signal from ESPN. The fix for me has been to pull the power plug on the Verizon box, plug it back in and wait for the reboot.
For you, I'd try doing a menu > restart and if that doesn't work, perhaps a Red Button Reset to get the box rebooted. You'll probably find things are back to normal. If so, then perhaps the problem was much the same as what I have been seeing -- garbled signal and/or bogus code coming from ESPN.