All, In celebration of the National Park Service's 100 year anniversary in 2016, NPS has designated 16 days in '16 as entrance fee-free days. http://www.nps.gov/findapark/feefreeparks.htm There are a total of 409 national parks, 127 of which charge an entrance fee. The entrance fee for these 127 NPS parks will be waived on the 16 designated days in '16. http://www.nps.gov/findapark/feefreeparksbystate.htm This sounds somewhat similar to a Michigan-based program with which you might be familiar. I wonder if there is any possible symmetry here? Hmm... Jim Jim Flury Technical Services Manager The Library Network 41365 Vincenti Court Novi, MI 48375 248-536-3100 x133 Fax 248-536-3098 jflury@tln.lib.mi.us