The problem with improv comedy is that the experts make it look real easy. You'll find yourself watching Waiting for Guffman, Reno 911 or Whose Line Is It Anyway? and somebody always says "Oh. I could do that!" (This person is generally among the least amusing people you know.) Another problem with improv comedy is that of inconsistency. For every piece of comedic gold that's mined by a good team of improv comics, there's probably hours of strained gags and failed whimsy that are unfit for human consumption. (I bet that most of Christopher Guest's outtakes aren't all that funny.)
Which brings us to a micro-budget improv comedy that's just now making a limited theatrical run before arriving (very quickly) on DVD. It's called Closing Escrow, the plot covers pretty much exactly what you'd expect, and it adheres firmly to the second problem I mentioned earlier: inconsistency. Closing Escrow runs about 90 minutes -- but if it'd been trimmed down to a lean 65 - 70 minutes, it'd be a whole lot funnier. (But then you'd have a lot of trouble selling it as a "real movie," I suppose.) Muddle through the lesser gags, though, and you'll find some really funny stuff here. And with the DVD arriving so quickly, the experience will only set you back a few bucks.