A 10-day Birthright trip becomes an 18-year test of friendship in Jonathan Spector’s “Birthright,” a sprawling, sharply funny and emotionally intricate drama now at MCC Theater. The play begins in 2006, after six young American Jews return from a free trip to Israel. They drink, trade hookup stories and jokingly call themselves “BirthLeft.” When they reunite in 2016 and again in 2024, the joke has accumulated the weight of marriages, children, professional setbacks, religious searching and political rupture. I went on Birthright shortly after college. I appreciated the opportunity — and the free ride — but left disappointed, exhausted and...