Ring in the summer solstice a day early by visiting the Science Museum of Minnesota's Big Back Yard.  

This seasonal feature of the museum includes a 9-hole miniature golf course demonstrating how water flows from mountain tops to the ocean and how the land is changed along the way.  Get lost in a maze of prairie plants native to Minnesota, discover the camera obscura, stroll through the Native American gardens before sitting down for a picnic lunch. 

This interactive exhibit is free with general admission.