Adventure Cycling is promoting Bike Your Park Day on September 24th, 2016.

From their site:

Discover new parks or experience your favorite parks in a new way. You can make it your own experience: ride your preferred distance; go with friends, family or join a group; bike on trails or roads. You can visit any type of public lands, whether it’s a national or state park, monument, or historic site, river, seashore, recreation area, preserve, forest, wildlife refuge, or parkway.

If you register your planned ride in a park (or other public lands) by September 5th, you will be entered to win a bike.

Details here: https://www.adventurecycling.org/about-us/40th-anniversary/bike-your-park-day/win-a-salsa-touring-bike/