An effort is under way to organize the world’s largest sing-along. The tune? Israel’s national anthem. Galia Albin, an Israeli businesswoman, is calling on people around the world to belt out “Hatikva” on May 7 — Israel’s 60th birthday — and break the Guinness World Record for the most people singing an anthem simultaneously. The event will commence at 10:50 p.m. Israel time. For more information, go to www.livehatikva.org.