As mentioned, Boulder CC And Lake Valley are your two best options in close proximity to Boulder. A bit further of a drive to Fox Acres in Longmont and Omni in Broomfield, as well. TPC Colorado in Berthoud is farther than those two.
What we lack in private courses, we more than make up for in public. Within ~45 minutes of Boulder, you have a lot of good options: Walnut Creek Golf Preserve and Riverdale Dunes are "links" style courses and worthy of repeat plays.
A bit further of a drive, but a hidden gem, is Highland Meadows in Windsor. Lots of the fun decisions and 1/2 pars and usually great conditions.
Boulder isn't that far from Wildhorse, Bayside and the rest of the sandhills either....