Building a Killer Web App In 45 Minutes

If you could gather together some of the smartest Web developers and ask them to brainstorm a killer app for you, what would you ask them to build? Oh, and they will only have 45 minutes to do it. That is the task set for me at the upcoming Future of Web Apps conference in Miami (Feb. 28 to March 1). I will be moderating a panel that will include Kevin Rose of Digg, Matt Mullenweg of WordPress, and several other Web app superstars (the conference organizers are trying to rope in Blaine Cook of Twitter and Cal Henderson of Flickr into the panel as well, schedules permitting). The goal of the panel: Come up with a killer Web app in 45 minutes.

So what should I have them build? Please vote for the choices below or, better yet, suggest an app yourself in comments. Who knows, some crack developer in the audience might just go ahead and build it. (BTW, any TechCrunch readers in Florida who want to go to the conference will get a 15 percent discount with this promotional code: discTCMIAMI08)