30 Rock 30 Rock

8 pm/ET Fox
There's been a lot of buzz about Brennan and Booth having sex this season, but after his brain surgery last week, will it happen in his hospital bed? That remains to be seen, though there are plenty of other reasons to tune in to tonight's fourth-season finale, including the return of Zack (Eric Millegan) and appearances by Brennan's dad (Ryan O'Neal), Booth's brother (Brendan Fehr) and, last but not least, Mötley Crüe, who just happen to be playing at a nightclub that's the scene of a murder. — Joe Friedrich

Grey's Anatomy
9 pm/ET ABC
Last week's Izzie stuff was quite the hankyganza. But all those wedding tears didn't wash her tumor away, and that'll have to be dealt with in tonight's two-hour season finale. Will she opt for surgery? Whatever happens to her is likely to be game-changing; that's what season finales are for. Also look for big George and Bailey news (no, they're not getting together) and Mark-Lexie developments. And what of the couple that was supposed to have gotten married? The Mer-Der soap opera still lives. — Paul Droesch

The Office
9 pm/ET NBC
A sterling Season 5 advanced with a multitude of plot-shifting crises. Among them: Andy and Angela's romance collapsed; Michael's relationship with Holly dissolved; and Michael's clash with bigwig Charles Miner was so major that he quit to start his own company. No, it hasn't always been a picnic for this gang. It's only fitting, then, that the season closes with...a picnic. The staffers attend this annual company outing, which finally brings together Michael and ex-flame Holly (Amy Ryan) — and Michael has big plans for her. Elsewhere, the Scranton branch tries to outwit, outplay and outlast the competition in a volleyball tournament. — Dean Maurer

CSI: Crime Scene Investigation
9 pm/ET CBS
Easygoing Ray (Laurence Fishburne) is forced to take lethal action for the first time in his brief CSI career as the ninth season comes to a conclusion. The case he's working focuses on murders linked to a poker scam that centers on rare poker chips from a bygone casino. Gerald McRaney and Cynthia Watros guest star as suspects in the crimes. — Tim Holland

30 Rock
9:31 pm/ET NBC
The Rockers face the music in the Season 3 finale, which hums along with a note-perfect roster of musical guest stars, including Sheryl Crow, Mary J. Blige, Elvis Costello, Clay Aiken and Adam Levine of Maroon 5. Alas, Jack's life lacks harmony: He tries to connect with his biological father (Alan Alda), but that's when the elder's health begins to suffer. In Liz biz, our heroine gets into a groove as a relationship expert. On the flip side, there's Tracy, who finally tries to overcome past high-school humiliations. — Dean Maurer