Seen over the years on my work commute in the Olympia, WA area:

A 20 something fellow riding a fenderless bike while wearing hip waders

Older(50+) asian gentleman riding a little girls bike (pink & white with 10"? wheels and streamers on the bar ends), he was dressed in a pinstripe suite & London Fog type raincoat, carrying a leather briefcase in one hand.

Elderly gentleman riding slowly on a 3 wheeled trike, carrying his walker in the basket between the rear wheels (not really funny, but made me smile when he waved)