With the rise of smartphones, more and more apps have been keeping tabs on where we are. Foursquare, Loopt, and even Facebook can keep track of you wherever you go, and of course, games are no different.

For instance, mobile games like the mega-popular Angry Birds let players download new levels if they visit the right locations, and other titles like Turf Wars are built to completely rely on GPS technology. We've seen myriad ways to use this technology in games, and this is just the beginning.

Now, for the question at hand: What would you do if you were to make a game using geolocation?

In this latest Game Design Challenge, we asked our readers to design a game that uses geolocation as part of its core gameplay.

What follows are the best and most original entries we received. Here are our top picks.

Best Entries

Jonathan Lawn, Communications Software Engineer, Carve-up (see page 2)

Michael Stephens, Ohio University Digital Media, Creatures Incorporated (see page 3)

Alexander Hermans, Computer Science Student at the RWTH Aachen University in Germany, (a)Mazing (see page 4)

Thomas Petzel, Student at Niederrhein University of Applied Sciences, Neighborhood Racing (see page 5)

Camila Carvalho / Rafael de Castro, Students at S.a.g.a - School of Art, Game and Animation, Break-in (see page 6)

William Klein, Tribeca Flashpoint Media Arts Academy, Photomaster (see page 7)

Faye Windsor-Smith, QA Tester for Codemasters, Photo Op - The App (see page 8)