"I am so in," Xochil (pronounced "Social") responded when I sent an email to friends trying to drum up some company. "This body has produced two humans. I can do anything."

With a partner in crime arranged and a meet-up plan determined, I affixed an empty pannier to my bike for the clothes I'd take off, and I headed downtown.

A Nude Among Nudes

When I arrived at the ride start in the waning 9pm light, thousands of people were preparing themselves for the seven-mile pedal. Across the museum's grassy front lawn, they were painting each other's bodies, wrapping strings of lights around the handlebars of their bikes and dancing to music blasted from battery-powered PA systems. Around the base of an elm tree, four topless women arranged each other's pastel tutu skirts, a 60-something man wearing only a red cape and Viking hat adjusted his bike, and a young naked couple posed for pictures, sometimes covering certain parts with helmets, sometimes not.

Still wearing my hoodie and shorts, I felt overdressed, but I couldn't muster the gumption to disrobe just yet. I headed instead for the long line at the museum entrance in hopes of getting inside before I met up with Xochil and began the ride.

Midway through a conversation with the naked man in front of me in line, I was hit with the panic-inducing realization that I would somehow need to remove my clothing before reaching the front desk of the museum to avoid overpaying. I developed a hasty plan that, admittedly, lacked subtlety.

Corey had just finished telling me about his work as an auto insurance agent when I took off my pants. Minutes later, between discussing recent weather patterns and running shoe preferences, I removed my shirt, then my bra.

Our conversation proceeded like nothing had changed. Corey did not seem to notice my sudden strip. Nor did anyone else. I exhaled. I'd done it.

Two minutes later, I entered the white-halled art museum behind other equally bare visitors and headed for Cyclepedia, a collection of particularly innovative bicycles curated by Vienna-based designer Michael Embacher. I tried to concentrate on the explanations of each bike's innovation (the first folding mountain bike! a ski bike designed for ice riding!), but I spent most of the time awed by the fact that no one but the docent was wearing clothes.

The Portland Art Museum offered ride participants after-hours admission to the bicycle-design exhibit Cyclepedia. With an entrance fee scale that encouraged the full buff -- $1 per article of clothing -- the museum fully embraced the spirit of the event. (Christina Cooke)

Skin to the Wind

The art museum's two entrances with views of separate horse statues complicated my reunion with Xochil, but we eventually managed to find each other. Retrieving my bike, which I'd locked to a pole half a block and a dense sea of riders away, proved our next challenge.