Looking for a free weekend out of the house?

Here is a link to all of the free weekends to get into a national park that usually charges an entrance fee. The first weekend is in January so get out of the house and see some nature away from the TV! I'm writing it on my calendar so I hope nothing else comes up that we need to do so I can take the baby out to a national park because I don't think he has ever been. I think my dad would love to go with us to do this. I will ask him if he wants to come too.