The hangover is every bit as funny as you have heard. And it works on 2 levels - not only is it a comedy, its also a mystery. Doug is getting married, and his 3 friends go to Vegas with him for a weekend of partying before he ties the knot. But when they wake up, Doug is gone, Stu is missing a tooth, the hotel room's a mess, and there are animals in their room. They can't remember a thing that happened the night before, and the movie is basically them trying to retrace their steps, figure out what happened, and (most importantly) find Doug.
Its a pretty simple setup - kind of reminds me of Dude, Where's My Car? It could have been a pretty mediocre comedy, but the actors elevate the material. They are all good, but Zach Galifianakis steals the show as the weird guy. My favorite line of his: "I'm not allowed within 200 feet of a school. Or a Chuck-E-Cheese." Got to love a movie that has the balls to make a pedophile joke and hit a baby in the face with a car door.
The movie is rated R, and for good reason. Don't go if you're easily offended, but I laughed out loud many times. This movie is Land of the Lost's polar opposite.
Speaking of Land of the Lost, I realize I didn't say much about it. I am going to elaborate on it a little. I don't know who the movie is for. The comedy elements fall so flat that I can't imagine anybody over the age of 10 finding it funny. There are also very simple fantasy elements, so I think its trying to be a kids movie.
But at the same time, there is a lot of sexual jokes that are not appropriate for kids under, I don't know, 13 or so. So maybe its not a kids movie. Its for teens. So it fails on both levels.
I used to like Will Ferrell a lot. But I think his success has gone to his head. Just like Adam Sandler, he now has the power to do whatever movies he wants, and he has total control over the material. Just like Adam Sandler, he was funny at first, and he can still be funny if he's used right, but the movies he makes as vehicles for himself are terrible. We have had 3 horrible Will Ferrell movies in a row: Land of the Lost, Step Brothers, and Semi-Pro. He needs to take a year or two off - try the Ben Affleck route. Let people miss him a little bit, then come back with supporting roles in good movies.
So to sum up: The Hangover = great, enjoyable, funny movie. Land of the Lost = none of those things.