The third season of the wonderfully smart and silly comedy The Big Bang Theory is even better than the first two. When Sheldon, Leonard, Howard, and Raj--the show's quartet of supreme geeks--return from their research expedition in the Arctic, Leonard and his adorable neighbor Penny fall into each other's arms. In most TV shows, losing that sexual tension would deflate the entire series, but the writers and performers of The Big Bang Theory navigate these treacherous waters with aplomb; after a weak couple of episodes, the show regains its bearings with faux tattoos, sneaky behavior modification, lessons in football, a dislocated shoulder, a trip to Switzerland, pot brownies, and the one true Ring. Guest appearances by comic book legend Stan Lee, Katee Sackhoff from Battlestar Galactica, and former Star Trek boy genius Will Wheaton as themselves are used to remarkably good effect, and Simon Helberg and Kunal Nayyar, as Howard and Raj, get better story lines than ever before.

But make no mistake: Jim Parsons, as Sheldon, drives the show. With Leonard (Johnny Galecki) and Penny (Kaley Cuoco) grappling with fairly conventional relationship issues, it falls to Sheldon to turn every potential cliché into an opportunity for unexpected lunacy. His combination of ruthless rationality, profound narcissism, and yawning neediness make Sheldon a remarkable comic creation, and Parsons plays him to the hilt. Even funnier than his relentless analytical approach to emotions is when he tries to be more human; his attempts to comfort Penny when she's injured are hilariously unnerving. Watching Sheldon "grow" over the course of The Big Bang Theory's progress is one of the show's greatest pleasures.