For instance, Weaver has a national reputation in competitive Frisbee circles for his elaborately choreographed freestyle routines. (He'll juggle and spin three of the plastic discs simultaneously.)
And every year during the holidays, he transforms his yard into a magic castle inhabited by more than 450 characters that he built by hand from plywood. Weaver's "Winter Wonderland" attracts thousands of viewers annually, many in tour buses, and has been recognized in national competitions.
After the San Francisco Chronicle ran a story in 2009 on "Rolling Through the Bay" both CBS and NBC broadcast segments about Weaver and his creation.
But he says he doesn't regret his lack of professional artistic and engineering credentials.
"If I'd done my art for a living, I'd never have made 'Rolling Through the Bay,'" he says. "I'd never, never have taken 3,000 hours and 42 years to build one piece."
If you go
"All Things Round" runs through Sept. 2, 2012, at the American Visionary Art Museum, 800 Key Highway. Museum hours are 10 a.m. to 6 p.m. Tuesdays through Sundays. Tickets are $6-$16. Call 410-244-1900 or go to avam.org