It's been more than 31 years since Robin Williams last starred in a weekly TV sitcom - "Mork & Mindy, which made him a star. He's back in a similarly manic role in The Crazy Ones (Thursday, 8 p.m., CBS/Ch. 2).This show isn't exactly what you might expect, but that's a good thing.Williams stars as Simon Roberts, a colorful advertising executive whose business has suffered because of his unsettled personal life and addiction problems.He works with his no-nonsense daughter, Sydney (Sarah Michelle Gellar, "Buffy the Vampie Slayer"), who tries - mostly unsuccessfully - to reign her father in.In Thursday's premiere, the agency is about to lose its biggest account, McDonald's. So Simon and his protégé Zach (James Wolk, "Mad Men") set out to convince Kelly Clarkson to sing an updated version of the old "You Deserve a Break Today" jingle. But she really wants to sing about sex.Clarkson, by the way, is absolutely terrific in her guest appearance. And Wolk and Williams make a great comedy team. Even Gellar displays more comedy chops than you might expect, although she's got some distance to go in that area.There are, predictably, plenty of crazy, over-the-top moments in "The Crazy Ones." And Williams does the same over-the-top schtick he was doing a third of a century ago on "Mork & Mindy."But there's a lot to like here, too. Particularly in the less outrageous moments, which work particularly well.This is a show worth checking out and worth giving a chance to develop.