If you are looking for a close, but fun area to take the family (maybe camp?) over this 4th of July weekend, may I recomend the Brainard Lake Recreation Area?
The entrance fee for the area is $9 and the pass is good for a week. There are seven different lakes to fish. The two lakes that you can drive right up to are Red Rocks Lake and Brainard...although the latter is the one you should fish if you go up this weekend. Red Rocks is a small lake that you pass shortly after entering the recreation area, and is so shallow it winter kills every year. The state will usually stock it with rainbow trout...but they are not this year. So don't bother stopping to fish it! Brainard Lake has a healthy population of wild brookies, though.
Long Lake and Mitchell Lake are excellent, as well. Fishing them involves only a short walk along a maintained trail...and can be worth it. The fishing is often better and there are fewer other people.
The recreation area is just west of Ward (30 min west of Boulder) You will see the signs on highway 7.