For four Hollywood comedians, the decision to fly to Israel to perform their stand-up routines is no joke. Avi Lieberman has convinced three more American comedians to come to Israel for the sixth annual benefit tour in support of Jerusalem's Crossroads Center for at-risk Anglo teens. Mark Schiff, who opens regularly for Jerry Seinfeld, John Mulrooney, who has appeared on The Tonight Show and hosted Comic Strip Live, and Reggie McFadden (pictured), who plays Larry David's Malibu neighbor cop in Curb Your Enthusiasm as well as appearing in HBO's Def Comedy Jam, are the trio this year who join comic forces with Lieberman here. Israeli-born Lieberman himself is arriving in Israel straight from a two-week tour of Afghanistan performing for the allied troops. The Crossroads Comedy Tour opens Wednesday at Jerusalem's The Lab, Thursday at Beit Shemesh's Club Tzora, next Saturday night (December 15) Raanana's Yad Labanim, and at Tel Aviv's ZOA House on December 16. All shows begin at 8:30 p.m. Details at 054-627-2867; tickets cost NIS 100.