It was directed by Jorma Taccone (Kevin Powell from Hot Rod and Mitch from graphics in Role Models singing "Rock me like a hurricaine"). Jorma is one of The Lonely Island (Andy Samberg, Akiva Schaffer and Jorma Taccone). They are a VERY funny trio and responsible for all the SNL digital shorts you see.
If I remember right I think it was Jorma, Will Forte and Kristen Wiig who wrote the majority of it. They said early on that this film would be a VERY hard R rating movie and from what one initial earlybird reviewer said that it's nuts and really funny, so who knows.
I admit I don't think all the clips in that red band trailer were 100% hilarious, but the film as a whole might be a real blast with the people they got in it.