How about Repo! The Genetic Opera
That is one of my favorite movies of all time, actually. All the songs in it are pretty catchy (excluding Seventeen, I don't think it fits with the theme) and the plot is pretty good. I'd say I've wasted at least 24 hours on it in total, and I think I could watch it for that long, straight.
Also, if muting was an option, the people I'd watch it with would sing along with me. That would be really fun!
EDIT: I could also watch either The Brave Little Toaster
or The Emperor's New Groove. Isn't that air conditioner just nightmare fuel
? He freaks out so badly that he basically has an aneurysm on camera! Also, the evil junkyard magnet scared the shit out of me when I was little. It still gives me chills to see his angry, red, foreboding figure approach the good guys.