ABC's Nightline has a fascinating story about Edward Kagin, an atheist and provocateur, who conducted a mass "de-baptism" of fellow non-believers to symbolically dry off the baptism waters:
Standing at a podium wearing a long brown monk's robe, Kagin read with the oratorical skill of a preacher from a set of pages in his hand and invited participants to come forward to be de-baptized.
He recited a few mock-Latin syllables, to the audience's amusement. An assistant produced a large hairdryer, labeled "Reason and Truth," and handed it to Kagin. The man who'd elected himself to be de-baptized stood before him. Kagin turned on the hairdryer, blowing the hot air in his face in an attempt to symbolically dry up his baptismal waters.
"Come forward now and receive the spirit of hot air that taketh away the stigma and taketh away the remnants of the stain of baptismal water," Kagin shouts.