Alright, we can all agree that Scary Movie was funny. It was a bit raunchy (sp check). But you sure did get a laugh.
For a really great scary movie, try Pitch Black starring Vin Diesel (the guy from Boiler room and Saving Private Ryan). This was a true scary movie with surprises all up in it. It should be out on video very soon...
Another good movie is "Orgasmo" by Trey Parker (it is NOT a porn). It's in the comedy section of any movie store (save Blockbuster, because the humor in that movie is a what they deem as "too much"). Another great classic is "A Clockwork Orange" by Stanley Kubrick.