Gross Reservoir is probably the best paddling just outside of Boulder.
Scenic lake, no powerboats, clean water.

Lonetree and Union have trolling speeds only. Carter Lake isn't bad,
but gets the powerboat traffic.

I have some trip reports at http://www.canoecolorado.com/trips for a
few local lakes and easy rivers. I'm trying to add more to the page,
but haven't had time.

The Rocky Mountain Canoe Club at http://www.rockymountaincanoeclub.org
is a good group and allows both canoes and kayaks. Dues are only $20
per year

- Eric