Hosted by WXRT’s Lin Brehmer and Marty Lennartz, the Rock for Kids 21st Annual Rock & Roll Auction will put an impressive stash of goodies up for bid—including autographed instruments, posters, and albums—beginning at 7 PM tonight at Park West (322 W. Armitage). Proceeds from the auction benefit Rock for Kids, a local nonprofit organization that provides free year-round musical education to what it calls “underserved” children and teens.