PHILADELPHIA—When not reviving Victorian hair jewelry or double-dutch jump-roping with friends in a local park, Gemma Waite, 29, is up to something similarly quirky, sources report. "I haven't seen Gemma since Christmas, when she did the living advent calendar thing in that old building downtown, but I'm sure she's planning something just as unexpected right now," said friend Simon Chan, who helped Waite fish a Michelin Man statue out of a canal several summers ago. Waite declined to be interviewed, saying she was busy organizing a spelling bee.