I can't say I've been through that situation with that particular film, but a similar situation was a regular occurrence about 6-7 years ago, when the great wild comedy of the moment was Old School (also directed by The Hangover helmer, Todd Phillips). I feel like that movie was on all the time at my house, where I lived with a bunch of other young guys. Of course, we had the DVD, but I'm certain if we'd only had the VOD option, the movie would have still been in heavy rotation.
That's why I'm not surprised to learn The Hangover is getting a lot of love On Demand.
CNN reports that The Hangover is the most-watched On Demand title of all time. The Golden Globe-winner is a fun movie to see over and over again, especially when you're slightly intoxicated and/or hanging out in a group.
Then again, my mom likes The Hangover too, and she has watched it at least once or twice via On Demand. Another reason I'm not surprised: the movie has a broad reach, unlike Twilight, which is only the second most-watched On Demand movie ever. As for third place: Gran Torino. Those three top films would make for an interesting triple-feature, I must admit. Though video-on-demand has been around for a long time (I assume the data includes the old days of pay-per-view?), it has become more popular in the last few years due to cable companies' heavy push of VOD options and the fact that many titles are available day-and-date with their DVD/Blu-ray release, rather than weeks or months later. This allows the very convenient On Demand platform to take precedence over hard copy video renting.
And now I wonder how many people watched sixth-placer Alvin and the Chipmunks, who would have been too embarrassed to rent it in person at a video store?