25 things to do around Boston for under $25
Jason Johns for The Boston Globe
Boston University's Judson B. Coit Observatory hosts public open nights every Wednesday night, weather permitting. Go to the observatory and see the stars up close using the facility's high-tech equipment free of charge.
Free of charge. Wednesdays 7:30 - 8:30(winter), 8:30 - 9:30 (summer). Call 617-353-2630 for status.