CSM Robotics Challenge. April 23, 9 a.m. 1 p.m., College of Southern Maryland, La Plata Campus, Center for Business and Industry Building, Room 113, 8730 Mitchell Road, La Plata. Nuts, bolts, gears, wheels and a programmer? Watch as local and high school teams bring their robots to the obstacle course battlefield, and fight for engineering glory and prizes. Funded through a National Science Foundation grant and the generous support of the Patuxent Partnership and the Charles County Technology Council. Free. 301-934-7556 or 301-870-3008, Ext. 7556 for Charles County; 240-725-5499, Ext. 7556 for St. Marys County or 443-550-6199, Ext. 7556 for Calvert County.