Few overrated came to my mind now:
Hangover - ok I understand the large incomes: it was kinda mainstream movie, so everyone went to see it, just for the hype of it, but... 7.9 rating on IMDB - wtf... Do people actually liked it that much? Never understood the hype about it, another lame comedy, quite poor acting, uniteresting characters. Though, don't get me wrong - I like dirty jokes, black humour and I ain't any kind of abstinent, far from that

but this was surely not my cup of tea
Paranormal Activity - also incomes are understandable (hype), it was kinda unique style of horror movie, but also unique boring. You are waiting, waiting, waiting for smth to happen, almost fell a sleep, but it doesn't. Also, young couple, so many nights were shown and... no sex scene, wtf
