The app: Chirp, which lets users transfer data via noises that sound an awful like a certain little droid. Funnily enough, the app is only available for iPhones – an Android version is planned for the future. It works like this: two or more phones have the app open, then one person “chirps” a link or photo or 140-character text and the phones within earshot receive the information. Right now, those are the three types of data you can transfer, but Chirp sees a big future in things like store coupons, paperless tickets, and even money transfers.
The BBC interviewed Chirp honcho Patrick Bergel, who talked about the ability to transfer data quickly to a crowd:

[Chirp] can also work over public address systems or radio transmissions – potentially allowing broadcasters a way to send up-to-date pictures or links to background information; or an advertiser to send coupons or snippets of a song or promotional video.

Maybe this could help folks in the Occupy movement from losing their voices and acting as human microphones. And (spoiler alert!) maybe there will be come a day some crazed hacker could get up in front of a room full of people, put his phone up to a microphone, and zap our bank accounts clean!

Oh and speaking of R2, somebody did this, AND I LOVE IT!