Since there is no official Foursquare app for Maemo and Nokia N900 Chili Technologies decided to make one. The name of the app is barrioSquare, barrio = (neighborhood in Spanish) + square (from foursquare) and it is available in the Extras Devel repository or via the direct download link in our downloads section. For those of you who are not familiar with Foursquare or haven't used the Foursquare app on some other platform click here to learn more. In short:
Foursquare is a cross between a friend-finder, a social city-guide and a game that rewards you for doing interesting things. We aim to build things to not only help you keep up with the places your friends go, but that encourage you to discover new places and challenge you to explore your neighborhood in new ways.
I will not bore you with details cos it is best to check the barrioSquare app yourself and I think you will like it. Please note that the app is still in development but apart from that it is totally usable.