The actual window theory, the "theory" postulated by the lead character that gives the film its title, is rubbish, and shows the lead character for what he is: a shallow, misguided waste of space. This "theory" has to do with the window of opportunity a guy has for getting a girl when they're "commitment-ready". Never mind that the lead character isn't commitment-ready, and isn't likely to be in the next decade or two.
I had a question about him returning to his hometown, but if the answer was given, I didn't hear it. I certainly didn't read it in the captioning or the subtitles, because there weren't any. There are strict laws about captioning for cable and television providers, but none that I'm aware of for producers of DVDs or videos. Quite frustrating if you're hearing impaired.
Ranting aside, here's my question: he's coming home to see his old friends, but where are his parents? Other parents are around and spoken of (if not seen). It's a bit odd.
The only redeeming quality, for me at least, was Tom Lenk. He was crazy funny in Buffy, and in this film his lines were well written for his character. Almost everything he does is funny.
Other than that, not much made sense. A guy is mad because one of his best friends is getting married and didn't tell him. They mad guy lives in L.A. in a decent apartment, but doesn't do anything. Yet he's able to scrounge up money and hop on a plane home ASAP. His friend is marrying his ex-girlfriend from high school. Maybe it's just me...but so what? The guy's 25, they broke up in high school (he broke up with her), PLUS he moved to LA and hasn't spoken to her since he left. Does that make any sense? Not to me.
The movie makes some feeble attempts at character development and resolution, and that's what saves it from the dreaded "1 star". Some of the attempts were half decent. Some were dreadful.
Again, if you like Tom Lenk (sadly, most people reading this, if there are any, don't know who Tom Henk is), watch it. He's funny. It's the only reason I rented it, and in that sense, I'm glad I watched it.