This movie is hysterical.  It is the funniest movie I have seen in years, I've seen it four times and it is funny every time.

It is about three high school seniors who are the 'Mystery Team.'  They solve local crimes; almost all of them are small meaningless 'crimes' that the local elementary school kids commit.  They are all grown-up kids, (think eleven-year old smarts in an eighteen-year old).  They are asked to solve a murder and hilarity ensues. 

If you like comedies like Role Models I would recommend this.