Why is such a thing being videotaped in the first place? "Hmmm. I'll do some sit-ups. That means I should bust out the video camera to watch it later!" Why is the monitor not plugged in to anything? That doesn't mean it is fake, just... weird.
EDIT: Not saying it is fake, but it could be faked with 3 different camera shots. Shot # 1 = cat jumping up on table. Shot # 2 = monitor falling. Shot # 3 = dude doing sit-ups, reacting and bumping into geetar. This would be easy to composite in After effects or even Final Cut Pro. Then, the video quality was lowered to add to its cheesiness/realism. Still, the monitor seems to bounce off of him so that would be the hard part. Why someone would want to fake something that really isn't that funny is baffling, though, unless it was just done for the experience.