Zach and Miri Make a Porno
(2006)

After making love to Miri (Elizabeth Banks) on film, Zack (Seth Rogen) finds he doesn't want to have sex with stripper Stacey (Porn Queen Katie Morgan) either on film or for "practice". Miri thinks he did have sex with her though, and plans to do her own scene with "Molester" Lester (Jason Mewes) to get back at him, even though Zack confesses his love to her and begs her not to do it.  Heartbroken, Zack leaves the set, his job and the apartment he sahres with Miri.

Weeks later, Delaney (Craig Robinson) tracks down Zack to have him finish the movie, since everyone in the cast and crew has seen their life change thanks to him. The reason the movie isn't finished is because Miri backed down from her sex scene with Lester. Zack storms to his old apartment, but finds a VERY naked Lester living with Miri. He professes his love to Miri anyway, and she professes hers to him in return; Lester was simply a roomate to help pay the rent.

Thanks Fleetwood!