This past weekend groups of developers gathered across the world for Foursquare's two-day global hackathon. Officially taking in place in New York City, San Francisco, Tokyo, Paris and unofficially in numerous other places, thousands of programmers built various add-on location-based apps which you can now vote on for your favorites here.

The weekend hacking is Foursquare's second attempt. Last year when they released their API they had 150 developers building apps. This year they have expanded their platform with new APIs.

Some samples include:

  • Accessible NYC, is web app to facilitate people who want to roam around NYC in wheelchairs. The app shows, the nearest train stations that have wheelchair access, the nearest parks that have accessible bathrooms, and also other parks/playgrounds that are accessible.

  • Flight Graph looks at your airport-related check-ins, graph your travel, and give you a snapshot of where your whirlwind travel has taken you.

  • CheckEat, which finds restaurants near your location and looks up their menu.
  • The Magic Muggle Clock, showing location similar to the clock described in the Potterworld books.

Prizes are mostly bragging rights, but there are some cool ones, including having your app output to the giant curved NASDAQ video wall near Times Square.