"I'm gonna tell you right now my … ticket said 8 p.m.!" said a suit-clad George Lopez, taking the stage at the United Center to kick off the Comedy Get Down tour. At 8:45 p.m. He had a few choice words for his fellow comedians. The show was actually starting four months late. Originally planned for March 11, the Comedy Get Down was rescheduled at the last minute "due to illness." Barely a month later Charlie Murphy, part of the original lineup, died from leukemia at the age of 57. "He died with gigs on the books," tweeted fellow comedian and Comedy Get Down member D.L. Hughley at the time. On Friday night, Murphy's absence was acknowledged several times, but most deeply in actor/comedian Eddie Griffin's set when he took a moment to "pour out some liquor" for his fallen friend. "I had the privilege and the pleasure to know and work with Charlie Murphy," he said seriously before tipping his glass and delivering a quick impression of Murphy in heaven. Aside from this solemn beat, the two-hour show — which featured 25-minute sets from Lopez and Griffin, and 30-minute sets from Hughley and Cedric the Entertainer — was high-energy, expletive-laden and button-pushing from start to finish, with Lopez holding down master of ceremonies duty between acts. While some typical comedy venues are large (C hicago Theatre, The Vic, Rosemont Theatre come to mind), arena comedy is a whole other level of big (the United Center's capacity is 23,500). Friday night's show was nowhere near capacity, but there were still more than a few people to keep entertained. On one hand, tell a joke and you've got thousands of possible laughs to pull from. But on the other, drop a mediocre punchline and the lukewarm reaction spread out among those thousands is extra mood-killing. With the stage in the center of the floor, the audience surrounding it on all sides and the four-sided Jumbotron projecting the performer's face no matter which way he turned, the comedians had nowhere to go for a contemplative water-drinking pause and no way to turn their back to the audience for even a second; an intimidating setup. Luckily, all four of these performers rank among the most experienced, with each enjoying