You have to see this movie.
"Mystery Team" is a parody of a phenomenon that was never itself a film: The Hardy Boys, Nancy Drew, and especially Encyclopedia Brown.
They manage to walk the line -- like the first Austin Powers film -- so that it's neither too wacky so you can't believe it and don't care about the characters, but not too boring that it's not full of subtle interplay.
The main gag is the innocence of the boys, who are thrust into adult situations continually. It's all about the acting in this film, and kudos especially to "Donald Glover". Dressing like an outrageous hobo, for example, could come across as really stupid in a film with Jim Carrey or Rob Schneider, who play up their roles too much. Donald manages to do it consistently.
On top of that, there are a several delightful plot twists that you won't see coming. The film tries to balance the boys basically being incompetent with allowing them to succeed in a way that isn't too corny.
It's laugh-out-loud funny throughout, a genuine must-see if you like intelligent edgy comedies. Note, it's not really meant to be a kids film. There's a lot of raunchy humor.
I'll give Mystery Team a well-earned 9 out of 10. It just missed a 10 because the ending was good but not quite a classic.
