The Princess Promenade Fitness Festival is a great yearly event for women and girls held along the American River Parkway.  The Festival is at Discovery Park and includes a 5K run and 3,15,26,55 or 64 mile bike rides.
Check out their web site for details.

The Sacramento Amateur Radio Club (SARC) and the Yolo Amateur Radio Society (YARS) team up to provide ham radio communications along the bike trail using portable base stations, bicycle-mobile, and pedestrian-mobile communications.