Charpentier's David et Jonathas at BAM will be wonderful. The fabulous baroque conductor William Christie and Les Arts Florissants. If you don't already love French baroque opera, you will when you hear them. Elegant melancholy and ravishing beauty.

Here is the incredibly stylish Atys they did at BAM last year:
http://www.youtube.com/watch?v=OXFsrCG51Pc