Letters to Santa, the Second City's annual 24-hour improv and music charity show, begins tonight at 6pm at Second City's e.t.c. In addition, representatives from Soma will do bra fittings (over clothing, of course) and the all-female comedy troupe Division St., hosts a bra drive for new and gently used women’s bras to benefit women in local shelters affiliated with the National Network to End Domestic Violence tonight from 8 to 10pm.