Self-guided stroll through historic downtown, art murals, and local shops. The best place to start would be in Old Town Square! Walk up and down College Ave and you'll find tons of shops to go in! A fun place to end is the Exchange!
We have a TON of breweries in Fort Collins--we are notoriously known for our beer. If you like your craft beer, then this is the place to go! New Belgium has a GREAT free tour to go on if you'd like to learn more about the beer making process (and its a great place to start or end your tour).
Hiking, boating, picnicking, and scenic views! Try stand up paddleboarding!
Beautiful hiking! Hike up to the "horse's tooth" or do a shorter hike to the waterfall! Maggie grew up hiking these EVERY Christmas Eve!
Mini-golf, go-karts, arcade!!!
Go whitewater rafting on the Poudre River!!! However, this is VERY dependent on water levels, so be sure to do your research (i.e. call).
Walking, biking, running along the river
Scenic hiking trails
Seasonal market with local foods and crafts
A relatively quick day trip, but absolutely gorgeous if you feel like you have time! Tons of hikes, drives, wildlife (great time of year for looking for elk), and alpine lakes! But, be sure to look into timed entry/reservations.