Shelf Road is one of my favorite climbing places in the western US and is truly a hidden gem!
Shelf Road is secluded, rural, and has great climbing. There are so many areas to choose from and it has a great diversity of route levels (mostly sport routes). My personal favorite area is "The Gallery" and "The Bank." Everyone is friendly and gives each other a hand.
Sand Gulch Campground, right within the climbing area, is also beautiful, especially at night when all the stars come out (great place for night photography!). The climbing areas are only a short hike away from the campground. The campground and climbing areas are super group friendly! You can go tent camping or small RV camping!
To get there from Boulder take the I-25 to Colorado Springs, take the exit for Canon City (It's easy to miss so stay alert). Go right at the first light, Dozier St, or right at the next light, Reynolds. Go north and the road will go left and then will cross Field Avenue - turn north here and you will be on a two lane road for almost 5 miles. There will be an intersection, where you will merge onto Fremont County Road 9. It's about 10 miles to the entrance on this road where there will be a sign.
This campground is a BLM, which means it's twice as rural and half as many crowds! It's $7 for regular sights and $14 for group sights (Tent or small RV). It's all first-come-first-serve so get there early, and if you can't get a site there's overflow parking in the north end, which almost the same as the sites. If you just want to go for the day there is day use parking in the NW area of the campground.
Check out Shelf Road on Summit Post for areas and routes.