After three days of party-hopping at the DNC, we're not sure how to discern ahead of time whether a party is going to be good. Last night, we came up with a litmus test: Did Walter Isaacson go? We'd been rather disappointed with the get-together being thrown at two different downtown bars by Politico and the Glover Park Group — a team of consultants that includes Howard Wolfson, the Hillary Clinton campaign's communications director. That is, until we stepped inside the second bar and found Isaacson near the door, declaring to a political staffer, "This is the great thing about not working on a campaign: I can party!" John Huey, Time editor-in-chief, seemed to be having a terrific time, too, though he said he hadn't been partying hard. "I've been partying medium." What does that mean? Until "one o'clock. Not bad." It was only 10:30 p.m. at that point, and Huey was bored. "I want to find another party," he declared, before giving Time managing editor Rick Stengel the universal hand signal for "Let's go!"

But Stengel stayed to drink and smoke and mingle. We spotted him later on the sidewalk making that classic late-night meet-up call: "Okay, I guess if you're going to call it a night..." He obviously wasn't talking to Isaacson, whom we spotted well past midnight at a Newsweek party held at the house of Scott Coors. There, we discovered another formula for party awesomeness: The number of cool people present increases in direct proportion to the number of miles you have to travel from downtown. We walked in the door and there were Cameron Crowe, J.J. Abrams — and Sean Penn. Abrams said he was planning to hit the convention floor tomorrow, and that Crowe had told him that being in Denver brought back old memories of being a young journalist and following Led Zeppelin there on tour. Penn was in town to host a rally for Ralph Nader the next day, but said he would be voting for Obama come November, "very reluctantly." Penn's problem? He said he doesn't think Obama is a champion of the Constitution, citing his support of the Patriot Act, among other things. But, he acknowledged, "There's nothing to do but elect and apply pressure."

Before we left, we tried to corner Isaacson to ask him the question that had been weighing on our minds all night: Who parties harder: Time or Newsweek? "Uh, thank you for asking," he said, before scurrying away. But the answer wasn't too hard to discern. We were at the best party of the convention so far, which happened to be sponsored by Newsweek, and the one Time staffer we'd spotted hadn't yet gotten loopy enough to say whatever was on his mind.