Oy is a system of between-stop informal gaming by Andy Huntington (Andy has a list of very interesting projects on his website at http://www.extraversion.co.uk/about.html).

The OY Project!
Participants send in text messages in the bus and have to answer question like in which sequence will we see some places on the bus route. The game also use GPS data of the bus. Nice idea. I like the approach in the sense of combination of different channels. Using SMS senders for information in and public displays for information out.