The dudes from EepyBird autographing Diet Coke bottles from their Mentos extravaganza.

There were a lot of diet Coke bottles, with specialized spray tops attached.

A machine-powered guitar.

Part of the display from the Exploratorium was a rope-throwing bicycle.

Ray called my attention to it.

A loop of rope is pulled onto a spinning bicycle rim, which throws it into the air, like an arc of water from a hose. The rope lands in a heap, and twists around for a second before getting sucked back in.

There were very few tangles, a real charming thing to look at.