Chautauqua Park: home of the Flatirons! If you want to see these iconic Boulder rock formations up close - whether for a hike or just a photo stop - you have to visit Chautauqua. You can actually use the Boulder hiker shuttle to get there from 8am - 8pm on Saturday's and Sunday's. If you go for a hike, be warned: it's a workout!!
Boulder has an extensive bike path network that Matt and Greta absolutely LOVE! It's great for bikers of all levels, and you can rent a bike either from a local shop or the Boulder B-Cycle bikes which you can find all around town. You may even spot Matt out on the trails the morning of the wedding! :)
Nederland is a really cute mountain town about an hour up the canyon from Boulder. There are plenty of hikes in the area, and the town is a great place to poke around and get lunch.