US National Parks offer fee-free days at more than 100 national parks that usually charge entrance fees (many parks offer free admission every day). Mark your calendar for these fee-free dates in 2012:

January 14-16 Martin Luther King Jr. weekend

April 21-29 National Park Week

June 9 Get Outdoors Day

September 29 National Public Lands Day

November 10-12 Veterans Day weekend

You'll see that our state offers these:
Harry S Truman National Historic Site
Jefferson National Expansion Memorial National Memorial (yay!, the Arch!)
Wilson's Creek National Battlefield