With a flip of the switch by Mayor Michael Bloomberg, the 74-foot Norway spruce from Pennsylvania was lit tonight at Rockefeller Center. As is customary, massive amounts of tourists and sentimental types gathered around to enjoy the lighting and performances by Justin Bieber, Michael Buble, and others. At 11 p.m, gridlock finally subsided after President Obama, in town for three fund-raisers, made his way out of the city via Randall’s Island Landing Zone, according to Gridlock Sam. The tree and its 30,000 lights stretching fives miles will be at Rockefeller Center generating congestion until January 7. ‘Tis the season to avoid midtown.