His 2003 album The Bathroom Wall was, quite frankly, crap. The same goes for his film-star debut in the there-and-gone Taxi. But then there’s that whole eight years’ worth of uncanny Saturday Night Live impressions and “Weekend Update” hijinks. His is an uneven comedy equation, yet the net sum is that Jimmy Fallon has scored himself the infinitely plum gig as Conan O’Brien’s replacement on Late Night, his boyishly likeable mug soon to be grinning behind the desk that’s helped launch so many other comedy careers. Yet the question remains: Is he actually funny on his own? Are his timing, material and persona up to snuff? If the Groundlings vet’s current chops-honing run—from last summer’s Montreal Just for Laughs Comedy Festival to Saturday’s local landing—hasn’t whipped him into shape by March 2, his career might follow that of SNL player/talk-show host Chevy Chase a bit too closely for comfort.