It seems that male-bonding or “bromance” is in these days (complete with an MTV reality show), so it was only natural that a movie be made.
That said, the film would have only been average if it wasn’t for the great chemistry between Rudd and Segel. Rudd is the ultimate straight man, while Segel is the crazy free spirit. Most of the comedy from the interactions between the two (and especially Rudd’s attempts to immitate Segel’s actions).
Also, I don’t know why, but Rudd’s leading roles all seem to have a musical element. Role Models was all about Kiss and this film it was Rush. I would also suspect that this is might be a reference to Segel previously playing a Rush fan on Freaks and Geeks.
Overall, it was a decent comedy with good laughs.