Diva Las Vegas
Diva Las Vegas is "a vacation, not a convention". It is arguably the most loosely organized event; the activities are listed when you register, and though there's an exception that requires a firm commitment, many of the activities require you to simply show up if you want to join others. I love how relaxed and unstructured it is; perfect if you have a friend or two, but want to make more. If you know someone going, however, make firm plans to meet; leaving it to chance almost assures you will not see each other.
Accommodations are left to the individual, and activities range all over Las Vegas. No fears if you've never been before...the organizers of DLV do an outstanding job of providing instructions on how to get to each location.