You can make a decent sitcom with one funny character. You can make a really good sitcom with a strong ensemble. But many of the great sitcoms create worlds — whether it's the insular world of Cheers or the expansive one of The Simpsons. To the ranks of these sitcoms welcome Parks and Recreation, the current sitcom most pleasant to live in. Pawnee, Ind., has grown over three-plus seasons into a fleshed-out world on the order of Springfield, complete with a mediasphere (like morning-zoo crew Crazy Ira and the Douche), a cross-county rival (snooty neighbor Eagleton, where the air smells like vanilla cupcakes) and a thriving local industry (the Sweetums junk-food company). And the cast of the Pawnee Parks and Rec department has become a Cheers-like chemistry factory, from aspiring pol Leslie Knope (sitcom MVP Amy Poehler) to gruff überman Ron Swanson (Nick Offerman) to sweetly nerdy bureaucrat Ben Wyatt (Adam Scott). Hail, Pawnee: first in friendship, fourth in obesity — and tops among fictional TV destinations. (NBC)