In a storage room on the top floor of one of the Smithsonian's fortresslike buildings, a legendary athlete is playing with artificial hearts. Forty-eight-year-old Rodney “Mutt” Mullen, who revolutionized skateboarding as a teen, first twists apart the plastic ventricles of a Jarvik-7 that once beat inside the chest of an Arizona man. He then moves on to inspect a 64-year-old heart pump composed of Erector Set parts, a gadget that a Yale medical student cobbled together for less than 25 bucks.

“Oh man, oh man, Erector Sets made me who I am!” Mullen tells the Smithsonian curators who invited him to Washington, DC, to explore their collections. “When I was a kid I had a double-decker bed, and I had this whole idea of using pulleys to get everything up to me on the top. And so the way I had it, I had strings going all over the place, controlling the light switches and everything through a command center, and I did all that with Erector Sets. My parents, they would leave me dinner on a tray so I wouldn't have to stop building.”

Mullen becomes even more effusive as his VIP tour continues. Objects such as a Civil War surgical kit and a vintage pacemaker inspire him to riff on topics ranging from the information-sharing practices of Native American tribes to the algorithms that astronomers use to locate quasars. His digressions lapse into incoherence at times—blank stares abound, for example, when he utters the phrase “the ones and zeros of the synaptic idiom” while describing how skateboarders learn their acrobatic tricks. But the curators are mostly dazzled by Mullen's intellectual dexterity, an unexpected trait in a man who has smashed face-first into concrete countless times.