DeadDropAR
Leave virtual money on real life objects, also geofenced location aware.
Used AReality3D awesome CV 
BattleHack NYC Winner
http://yosun.me/2013/08/07/making-deaddropar-in-battlehack-nyc/
My co-hack partner was a ditzy Unity frontend only person, so he just did the form-based UX design, but he hasn’t done that many projects so he actually described it on his linkedin as well.
Some misc news articles about this:
http://venturebeat.com/person/yosun-chang/
http://www.forbes.com/sites/tomgroenfeldt/2014/01/30/paypal-hackathons-innovate-in-finance/
https://www.paypal-community.com/t5/PayPal-Forward/One-Hot-New-York-Battle-Hack/ba-p/781083
http://www.geek.com/mobile/paypal-global-battlehack-1562948/