The Staerkel Planetarium has shows throughout the semester. Check with your professor is a show is permissible, but light shows and kid-oriented shows are not allowed. See the planetarium website for schedules, descriptions, and prices.
The Champaign-Urbana Astronomical Society (CUAS) has the Family Skywatch at Prairie Winds Observatory on September 11 and October 9.
The CUAS also has a Starwatch at Middle Fork Forest Preserve on October 2 starting at 6:30 PM. (map)
The University of Illinois has an open house at their observatory on the first Friday of each month. They are streaming these on Twitch at this time.
Watch the Saturday Physics for Everyone lectures at 10:15 am.
Watch the Astronomy on Tap discussions on the third Thursday of each month at 6 pm.