Saturday is National Public Lands Day. National Public Lands Day is a fee-free entrance day at many federal public lands including national parks. All of Alabama's 22 State Parks are also offering free admission this day, too. Search for a site near you or find one and take a day trip.
Saturday is also Museum Day. See the post for a link to get free admission tickets to participating museums. (Hint: Old Alabama Town is one of the participating venues.)
I heard about one neighborhood yard sale this weekend but there may be more.
7 am-11 am Cloverdale-Idlewild Neighborhood Yard Sale (Montgomery)
3100 Block of Cloverdale Road in Montgomery