Fringe

Fringe
9/8c Fox
All the recent revelations and soul-searching about Peter's real identity — and keeping it from him — must be driving Olivia and Walter crazy. So if they need a little distraction from this moral dilemma, their investigation into the deaths of passengers on a commuter train should do it. But the case, characterized by a mysterious energy drain from the corpses and their electronic gadgets, also introduces them to a man named Alistair Peck (Peter Weller) who may have had something to do with it. — Joe Friedrich

CSI: Crime Scene Investigation

9/8c CBS
Fans of Hodges (Wallace Langham) and Wendy (Liz Vassey) are in for a treat when the two lab rats take center stage in an episode written by the two stars. Hodges and Wendy take a group of high-school CSI explorer scouts on a field trip. Along the way, the two somewhat embellish their roles in solving cases and take their field assignment a bit too seriously which, of course, leads to case complications. — Tim Holland

Saturday Night Live in the 2000s: Time and Again
9/8c NBC
The ins and outs — and highs and woes — of the live-wire, late-night comedy show in the 2000s are recalled in this ready-for-prime-time documentary. Here's a look at the laugher's memorable sketches, political skewerings, digital shorts, "Weekend Update" bits and talented female players. Framing the special are clips, backstage anecdotes and interviews with a gallery of SNL stars, including creator and executive producer Lorne Michaels, Jimmy Fallon, Will Ferrell, Tina Fey, Bill Hader, Chris Kattan, Seth Meyers, Tracy Morgan, Amy Poehler, Maya Rudolph, Andy Samberg, Molly Shannon and Kristen Wiig. — Dean Maurer

Supernatural
9/8c CW
The series celebrates its 100th episode with surprises that may shock even die-hard fans. The hour centers on the Archangel Michael, who deals with a major crisis when the other angels decide they don't need him anymore. Along the way, someone who was thought to be long dead returns, and a major character makes the ultimate sacrifice. — Tim Holland

Project Runway
10/9c Lifetime
A runway landing begins when the clothes-themed reality competition begins sewing up its seventh season with Part 1 of the two-part finale. There was over-the-top drama in last week's big-top episode featuring clothes inspired by the circus — the Greatest Sew on Earth, if you will. Fan favorite Anthony Williams was ousted; Emilio and Seth Aaron cemented their place in the finale; and it was revealed that nemeses Mila and Jay will battle for the third coveted Fashion Week slot tonight. All four will be under the Gunn, as avuncular mentor Tim Gunn visits them at their respective abodes and reports on the progress of their lines. — Dean Maurer