The National Building Museum in Washington DC just opened a one of a kind exhibit featuring a 12-hole mini-golf course, which will be up until Labor Day, September 3. Designed by leading local architects, landscape architects, and contractors, their creations allow visitors to challenge friends and family to a round of mini-golf with air-conditioned comfort in the museum. Games cost $5 for non-members and $3 for members. For more information on the exhibit, please visit here. More images after the break.