"The Curse of the Black Pearl" part 1, part 2 (or: THIS IS A DISNEY MOVIE!)
There's some plot somewhere about a curse and gold medallions, but nobody really cares because it has JOHNNY DEPP and ORLANDO BLOOM running around in 18th century costumes, getting into sword fights and looking pretty.
Spoiler rating: 4
[pic 1, pic 2, pic 3, pic 4]

"Dead Man's Chest" part 1, part 2 (or: Plot? What Plot?)
To save Elizabeth, Will goes on a quest for Jack's compass and the excised-but-still-beating heart of Davy Jones. Yeah, it doesn't make a whole lot of sense to me either, but it's pretty fun anyway.
Spoiler rating: 5 (just watch the last twenty minutes or so, then you can read it)
[pic 1, pic 2, pic 3, pic 4, pic 5]

"At World's End" part 1, part 2 (or: THIS IS A BRUCKHEIMER MOVIE!)
Jack is rescued from the Locker so the pirate lords of the Brethren Court can release the spirit of Calypso...or something. Whatever the plot is, it involves a LOT of explosions and swordfighting and a giant whirlpool. Will is hell bent on rescuing his father and Elizabeth kicks all sorts of ass as the Pirate King of the Brethren Court. Oh, and there's repeated mention of stabbing Jones' heart and taking over the Dutchperson. That's probably important.
Spoiler rating: 5
[pic 1, pic 2, pic 3, pic 4, pic 5, pic 6]*

*Font on this set of pictures is "Caribbean", found on dafont.com. Pictures from cap_it livejournal.