Who says grown-ups can't play on the swings? As if it's not fun enough, try swinging on a moving BART train! Last week a group of unknown people went out and successfully installed swings on BART between 24th and Mission. Maybe not so safe when BART does the swinging for you, but tons of fun and it added a bit of lighthearted playfulness to the ride of a few folks.

Check out the full Flickr set here.

Photos courtesy of y3rdua via Flickr