I had the exact same shit happen to me awhile back. Watched some shit, everything was good, went to bed, woke up, turned shit back on, no display. For me, using the other port solved my issue though.
Was there a thunderstorm? (:O)
If not, my idea would be disconnect monitor from everything, blow out it's ports with a can of air or w/e and leave it sit for at least 30 minutes, but if you got other things to do, leave it as long as you're willing to and then re-connect, see what happens.
I once had a tv do some wonky shit due to, presumably, static electricity. Stopped working, and couldn't get it to display shit, tried again and again day after day but nothing, so I unplugged that shit, left it for a day, plugged it back in and it worked. *shrug*
As a bonus, I'd do the same to your comp, no power for a bit. Might reset something. Computers are fickle that way.