Another gorgeous lake - the Silver Flat Lake Reservoir. This is a few miles up American Fork Canyon. The drive is a little rough/scary (although I admit I'm a huge chicken when I'm not driving) (control issues much?), but it's worth it.
We had a picnic on the sandy beach, then went wading/swimming despite the fact that it was FREEZING. (I think we went in May or June, can't remember.) After a bit of swimming we were ready for a short hike. We only hiked a little way up (we were already worn out) (plus I'm lazy), but you can hike from Silver Lake Flat Reservoir up to the actual Silver Lake (google it, there's tons of information online about the hike). We stopped to climb on a few rocks and play in the river.
You can fish there, or camp (but, somewhat oddly, you can't camp within 1/2 mile of the lake). More info here: http://www.utahfishinginfo.com/utahlakes/silverlakeflat.php