Emily Hodgson and Emilie Riis, staffers at London ad agency 18 Feet & Rising, have gone to the web to pester Nike. They've created Purple Unicorn Planet, a site that looks like a site selling various Nike training shoes. But when one clicks on the sneakers one gets a message that Nike doesn't make those shoes in women's sizes. They urge you to share a letter of protest with Nike (it begins, "Somewhere in Swoosh Central, there's been an oversight"). There's also a Twitter feed, @PunicornP, and hashtag #PleaseJustDoIt.