Mosquito Creek - The only longer, continuous stretch of whitewater that's less than a 2-hour drive from Yellowknife. The river is narrow, rocky and somewhat steep for Grade II, which gives it a bit of a creeky feel, without being full-on creek boating.
The paddling is generally good only during spring run-off in late May and possibly early June. As water levels drop, it becomes too slow and shallow to be fun.