Festival purists are probably foaming at the mouth over Tribeca's Opening Night feature, Baby Mama. Mama stars Tina Fey and Amy Poehler, the former and current female halves of Saturday Night Live's "Weekend Update" segment. Opening your festival with a film populated with SNL-ers must violate some rule of festival scheduling; it's an outright dare for the Man Upstairs to start the Apocalypse. Mama opens Friday, but gets its moment to shine tonight at the Ziegfeld, the most uncomfortable upscale theater in New York City. Sure it looks pretty, with its old-style presentation, its red carpeting and its balcony, but the seats feel imported from an old grindhouse on the Forty-Deuce. I guess the flappers in Flo Ziegfeld's time had harder asses.

I shouldn't act as if Tribeca is the only festival interspersing mainstream fare with indie whiners: Cannes has Indy IV: Attack of the Jones unspooling on May 18th. Tribeca also has Speed Racer, the 25th anniversary showing of Michael Jackson's Thriller (who knew that film's zombie make-up was a harbinger of Jackson's current appearance?), and David Mamet's Redbelt. That last film features Chiwetel Ejiofor rolling around on the floor in the homoerotic embrace of mixed martial arts. It sounds like an odd subject for Mr. Glengarry Glen Ross unless you've seen any uncensored interviews with Ultimate Fighting Championship president Dana White. That guy sounds like a Mamet character; whenever he's on TV he's beeped so much it sounds like the old Emergency Broadcast System.

For doc lovers, Tribeca has Errol Morris' latest film and an African documentary produced by Madonna. Baby Mama notwithstanding, if the fest schedulers really wanted to start the Four Horseman's approach, they would have mounted a showing of Filth and Wisdom, Madge's directorial debut. Maybe Lincoln Center can pick that one up for the NYFF.