WHO IS CHAI? Chai BBG #1728 is the local BBYO chapter centralized in Foster City, San Mateo, San Carlos, Belmont, Redwood City, Redwood Shores, Burlingame, and Millbrae. BBYO is a Jewish youth group organization, with regions spanning across the world. Chai BBG is a part of Central Region West (CRW), which comprises 19 chapters spanning from Marin to San Jose and all through the East Bay, representing over 950 Jewish teens in the area.