Trading Places meets Tin Men.

Ben Stiller and Jack Black are neighbours and work partners. Black plays a man without ideas, who invents a dog poo vanishing spray (straight up!) and its an overnight success and turns him into a millionaire. His friend (Stiller) passes up the chance to make some money for himself out of the invention and he and his wife (Rachel Weisz) play the pauper neighbours to Black's rich family now living right next door.

The comedy is uneven and the laughs don't come easily, especially when a hobo called J-Man (why?) walks into the drama. Christopher Walken does eccentricity well, but just being off the wall isn't necessarily funny.

The ubiquitous Stiller is everywhere right now (Dodgeball, Anchorman, et al) and he does his best with the wacky material, but envy over money doesn't always produce a great yield of jokes, which this film testifies only too well.

Beyond the first take of a sumptuous house next to a modest one, parading the haves next to the have-nots has a limited gag life. See Anchorman instead would be my advice