MUSIC: The Los Angeles Master Chorale performs Handel's Messiah tonight at the Walt Disney Concert Hall. But the audience has a part in this fun sing-along. So get your "hallelujah" ready. 7:30 pm // Walt Disney Concert Hall // 111 South Grand Avenue, Los Angeles // $16-$69 (Cheaper tickets are getting scarce). OUTDOORS: Santa Monica pretends its Pershing Square with an ice rink of its own. It’s a stone’s throw away from the Third Street......