•She's back, and maybe not so bad. Michelle Trachtenberg's Georgina returns to Gossip Girl (CW, tonight, 8 ET/PT), and apparently she has undergone a major transformation.

•Leonard goes to Vegas on The Big Bang Theory (CBS, 8 ET/PT), leaving Sheldon locked out. You just know that's bad news for Penny.

•Chuck (NBC, 8 ET/PT) ends its season tonight with a hoped-for wedding, a host of guest stars — including Scott Bakula, Chevy Chase, Morgan Fairchild and Bruce Boxleitner — and its future in considerable doubt. It would be nice to see Chuck get another chance, but if it doesn't, let's hope the show's stars are all back on TV soon.

•No such worries for Heroes (NBC, 9 ET/PT), which already has been extended for another season. Someone dies tonight, though that doesn't necessarily mean someone leaves.

•Now here's a welcome return. Chelsea sets Alan up on a blind date with a new friend on Two and a Half Men (CBS, 9 ET/PT) — and the friend turns out to be Rose, once again played by the adorable Melanie Lynskey.

•They're putting a wickedly funny reality spin on murder over at CSI: Miami (CBS, 10 ET/PT) as a TV dating show turns homicidal. Think of it as CBS' revenge on an unfortunately long-lived ABC hit.