The wildfires are pretty well contained now. With the rain over the last couple of days, I'd bet they're just about out.
If you like to eat and drink, there's a lot of good restaurants in Boulder (Jax Fish House ($$) and Q's ($$$) are a couple of my favorites). If the weather is nice, there's also nice hiking close to town. There are a couple of trailheads up near NCAR and several up Baseline near Chataqua. I'm sure the folks at NIST could give you plenty of other tips.
Downtown Denver is only a 30 minute drive and there's lots of nightlife there. If you can get away for an afternoon, try and catch an afternoon baseball game at Coors Field. The Rockies are playing at home all next week and have an afternoon game on Thursday. Otherwise, there are four night games scheduled. Tickets aren't too hard to come by.
As far as firearms related things, there's a Highpower match at the Boulder Rifle Club on the north edge of town (yes, there are guns in the Socialist Paradise... at least for now) on Saturday 9/23. There is also a gun show at the Denver Merchandise Mart on 9/23 and 9/24.