If you're looking for a free family event to go to tonight, meet up with a docent and other attendees to watch the bats emerging from their roost underneath two Bat Bridges - River and Campbell and Pantano and 22nd Street at 6:45. 

Arizona-Sonora Desert Museum docents will have bat detectors and other hands on materials.

Meeting location is St. Phillips Plaza, 4280 N. Campbell Ave. for the Campbell bridge, and Pantano River Park at Pantano and 22nd for the east side bridge.