In the theater? Boogie Nights.
My friend and I didn't know a goddamn thing about Paul Thomas Anderson when we went to the premiere. All we knew was that Heather Graham got naked in this movie about porn stars. We'd both had massive crushes on Heather ever since License to Drive... A crush which was only strengthened by her appearance in Swingers.
It turned out that the great nudity was only a bonus to what ended up being an amazing film with brilliant performances from everyone... INCLUDING Marky Mark. My friend and I ended up going to see Boogie Nights on the big screen close to 20 times. It helped that I had just gotten a job as an usher at a theater when the movie got it's second run, so we could see it for free. It also became a point of local pride since PTA was North East Ohio television royalty, and my friend and I wanted to follow in his footsteps