Berlin Cameron/Red Cell's Avi Dan and his son Michael were leaving TriBeCa eatery Nobu last Tuesday evening when they almost literally bumped into Paul McCartney and his wife, Heather Mills, who were waiting to be seated. "You're my hero!" Dan cried out. The ex-Beatle smiled and replied, "Hi. Thanks." ... Ground Zero in Marina del Rey, Calif., threw a big party last Thursday to celebrate the premiere of Wickedly Perfect, the CBS show in which a dozen contestants —including Denise Crandall, wife of Ground Zero cd Court Crandall —do battle by cooking, designing and party planning their little hearts out. ... After a year off it, IPG's corporate communications chief, Philippe Krakowsky, is back on PRWeek's list of the 10 Most Daunting Jobs in PR. Came in at No. 10, the same rank as in '02. In the No. 1 slot? Richard Kline of Omnicom's Fleishman-Hillard in L.A., the shop accused of overbilling the L.A. Department of Water and Power. ... Eleven in San Francisco, which took its name from This Is Spinal Tap ("This one goes to eleven"), can't get the movie off its mind. It just expanded its offices and held a contest to give the new floor a different "company name" for the directory in the lobby. The winner: "The Big Bottom Holding Company." ... Volvo brought a little Hollywood to the L.A. Auto Show last week. In addition to showing off the XC90 with transverse-mounted V8, it welcomed Jim Belushi (playing with Los Lobos) and showed a "Volvo for Life" documentary about cancer patients running lemonade stands and Rwandan orphans greeting outgoing Volvo execs. "That hit the demo perfectly," says Skip Streets of Compete, the Boston ad-effectiveness company. "It made me laugh and cry."