Viva Las Vegas is an old-school Celebrity-PB game. You create a character, you set them in Las Vegas, you socialize and move within the game. Yeah, we know, Vegas is probably the most popular setting for PB games. But there's just so much electricity about Las Vegas, we couldn't resist.
VLV's unique twist is that it centers around a fictional 'blogosphere' sponsored by one of Vegas' newspapers. The inspiration for this came from free papers like BostonNOW and Metro who sponsor blogspots where people can meet each other and report news. Both papers even post submissions from their bloggers.
Add a Craigslist-inspired classified community, the aspect of IM interaction and people following the action "off" the blogosphere and on to the Strip and beyond, and you have the elements for a great RPG.