The guys from TU Munich have the perfect solution for you:
Augmented Farmville could be one heck of a layer for Layar/Junaio/Wikitude once better positioning is available. Think of the gold rush to get a virtual plot in major cities, imagine Times Square as a flower bed! Using real meteorological data to those virtual farms would add another interesting and educational twist. It may be the most stupid idea I have ever featured in this blog, but then again, nobody would guess that a farm simulator will be one of the most successful games in 2010.