I built hrnw to connect people who are in the same location at the same time. Think of it as an anonymous chatroom with everyone else who is also on the app at the same time, within a few hundred feet or so of you. I think it would be fun for bars, concerts, conferences, or really any other social gatherings.
Please let me know what you think, if you'd like to know about the stack, and if you see any big issues.
I think the previous incarnations of this were a bit too creepy and focussed way too much on the location-based aspects of it rather than the experience of augmenting "what's going on around you right now". They were also way too early... Users weren't ready to allow an application to use their location a few years ago.