Wingfield Park, which is actually five parks in one, is a tranquil, relatively smoke-free place to unwind beside the gorgeous Truckee River. You can often watch whitewater enthusiasts challenging the rapids, or even try it yourself if you're game. During warm weather, virtually every weekend features special events and activities, ranging from concerts and movies to festivals. All free.
If you go:
Mothers Day is an especially good time to go to Wingfield Park, though it's often a bit chilly. There is a River Festival that includes a kayak competition.
Links:

300 West First Street
Reno, Nevada 89501 USA
renodirect@reno.gov
Mailing address:
P.O. Box 1900
Reno, NV 89505 USA
Phone Numbers:
Reno Parks and Recreation
+1 (775) 334-2414
+1 (775) 334-2414