Giant long-term capture the flag

I can't take all the credit for this as some kids were playing it on an entire city block in Oakland. But they kind of got shut down which is actually pretty sad.

But I'd like to make it even bigger. The game would take place over an entire city and would span a couple of days or weeks. The way I see this working is to use some kind of GPS device as the flag. And make it so everyone could track the device online or with their phones. If you get tagged (which would be awesome because of the tracking and the whole being in public thing) then "jail" lasts for an entire day instead of you getting rescued. Maybe all the players should be GPS enabled, too?

There are probably some pretty serious rules that need to get established before you played it but this sounds super fun. I think a high-tech version of capture the flag on a huge scale would be epic.