Last weekend, the National Building Museum in Washington, D.C., opened a 10,000 square-foot ball pit to the general public, and everyone cheered that, finally, someone made their childhood dreams come true.

A shoebill is displayed at Ueno Zoo in Tokyo August 28, 2012. (Photo by Itsuo Inouye/Associated Press)

An Anti-Capitalist protestor from the Occupy LSX movement at St. Paul's Cathedral on February 22, 2012 in London, England. (Photo by Matthew Lloyd/Getty Images)

Local actor Colin Retallick plays the role of St. Piran during the annual processional play to celebrate St. Piran, patron saint of tinners and regarded by many as Cornwall's premier saint, on March 4, 2012 in Perranporth, England. (Photo by Matt Cardy/Getty Images)

Archie McQuater, 82-year-old clockmaker at Craiglea clocks, adjusts a clock face to British Summer Time (BST) on March 25, 2011 in Edinburgh, Scotland. Clocks will be put forward by one hour at 1:00 AM GMT on Sunday March 27, 2011 officially the start of British Summer Time. British Summer Time will end this year on October 30. (Photo by Jeff J Mitchell/Getty Images)

A model showcases designs by Antonia Paris during the Women's RTW 3 catwalk during Rosemount Australian Fashion Week Spring/Summer 2011/12 at Overseas Passenger Terminal on May 5, 2011 in Sydney, Australia. (Photo by Stefan Gosatti/Getty Images)

A model showcases designs by Isola by Megan Gale on the catwalk at the David Jones Spring/Summer 2011 season launch at the Royal Hall of Industries, Moore Park on August 3, 2011 in Sydney, Australia. (Photo by Lisa Maree Williams/Getty Images)