How can Barry Levinson possibly assemble white-hot comedy talents Ben Stiller and Jack Black, the gorgeous Rachel Weisz, old pro Christopher Walken and still deliver such a humourless stinker?Stiller and Black are friends until the latter invents a spray to make dog mess vanish and becomes a conspicuous consuming multi-millionaire.The premises is thin but sound enough in the right hands to have been a springboard for some great bitching between the two stars but all concerned overplay every hand, every chance they can.Stiller and Black are simply not funny for way too much of the time, Weisz looks sensational as always but is criminally underused and, with the exception of Walken as a batty barfly who urges Stiller's character to take revenge, it's a turgid trudge to the end of this strained farce.