In a break from its usual filmed style, NBC's "30 Rock" went live Thursday night with an episode that was full of fun and, yes, very lively. As promised, the setup for the episode had boss Jack Donaghy (Alec Baldwin) delivering the bad news that, as a cost-cutting measure, "TGS," the fictitious show-within-a-show produced by Liz Lemon (series star Tina Fey), would henceforth be filmed, not broadcast live.