We've just been having a play with Creative Everyone, which is a corker of site, put together by Daniel Howells from Kulor, and Mike Sullivan from Mister. The tagline of the site is 'Never miss a creative event again', which sums it up pretty neatly. The site is a collaborative diary of creative events, ranging across the full spectrum of creative disciplines; you can filter the listings according to your own tastes, and also according to your local city. You can add in events you're planning on going to yourself, see which other site members are going, and export your calendar to Google and iCal.
The design is really elegant and intuitive - at the moment it's still in Beta phase, and just limited to some major US and UK cities (Boston, Los Angeles, New York and San Francisco / Edinburgh, Glasgow, Liverpool, London, Manchester), but the boys are promising to do much more when they get the chance. We'd love to see it properly hooked up to Facebook, and to have a customisable alert system, so that you get warned when exhibitions are starting and ending. But we can already see this being a really useful site. Ace.