Music -- The ubiquitous cellist Yo-Yo Ma will be lending his talents to the Boston Youth Symphony as they celebrate their 50th anniversary. Symphony Hall, 3:00 pm, $50 to $75. We gasped at the price, too, but 50th anniversaries don't happen every day. -- DeVotchKa and Basia Bulat may not make sense to you as words, but trust us when we say that their equally strange-but-wonderful folk-rock will transport you--maybe even to the point......