Posted Tuesday, May 29, 2012 --- 6:15 a.m.

MADISON, Wis. (AP) -- Outdoor lovers can visit Wisconsin state parks for free this weekend.

The Department of Natural Resources will hold its annual State Parks Open House Day on Sunday. The agency will waive admission stickers and trail passes.

Visitors who stop at one of 49 parks participating in the "Read to Lead at Wisconsin State Parks" program can check out a book paired with that park that will help them learn more about nature and the environment. The program challenges children between the ages of 5 and 9 to read nature books from a DNR-compiled list.

Any child who finishes 20 or more books from the list can enter a drawing to win a Kindle Fire and other prices.

Copyright 2012. The Associated Press.