CellGuided is a modern version of traditional treasure hunts. Use a mobile phone to receive directions and solve clues. Any mobile phone will work! No need to fiddle with GPS, SMS, installing applications, etc.

With CellGuided you can create routes, share them with your friends or publish them for all to enjoy.

Read more about it here.

This project is an attempt to gather data from various free and open aerial imagery datasources around the world, and use them to create a single, coherent open world view.

Read more about it here.

DIYcity was created in October 2008 by John Geraci. The site explores the idea that open, participatory web technologies, applied to city living patterns, infrastructure and services, can radically transform cities as we know them, making them more efficient, more livable and more sustainable.

People all over the world are invited to exchange ideas on how they can reinvent their local areas, offering examples of applications, open source code, and anything else that will help develop a collective approach to building these new DIY cities.

Read more about it here.

SKOUT enables users of virtually any mobile device currently available to create content—messages, photos, videos—with their handsets and post it to the SKOUT network from any location. SKOUT’s unique location-based software notifies other logged-in users within a predefined radius that someone nearby has posted new information. This enables end users, if they choose, to act and connect live. Whether it’s meeting a friend based on a picture of their location, dropping in on a nearby happy hour promoted by a local bar owner, or taking a chance and meeting someone new because they just posted a cool video, SKOUT offers a new way for people to have fun and connect with others.

Read more about it here.

magewiki makes it easy to create hyperlinks to anything in the world! Take a picture of anything and add comments, rants & raves. We do image recognition to connect you with other users who saw the same image. Hide notes in real-world objects or tell people about how good that album is, or where that band on the poster is playing or anything you can imagine!

Read more about it here.

The Lost Ring is an alternate reality game (ARG) revolving around a fictional Olympic sport that disappeared 2000 years ago that was created by McDonald’s as part of their marketing for the 2008 Olympic Games in Beijing, China.

Read more about it here.

Praized enables publishers to provide their users with an easy way to recommend local places to each other. It’s the first distributed local search platform designed specifically for social media sites like blogs, social networks and other vertical sites (basically, everywhere there’s a vibrant community). There’s no easier way to capture, organize and aggregate local conversations about places.

Read more about it here.

Squidoo is a hand-built collection of half a million pages built by people just like you.

Squidoo is about finding people when you care what they know instead of who they know.

Read more about it here.

Hostip.info is a community-based project to geolocate IP addresses, making the database freely available (see below) but it needs you to put in your city to make it work. It only takes 10 seconds, and you’ll get a warm fuzzy feeling of ‘doing the right thing’

Read more about it here.

Welcome to Localmouth where you can find and share information about your local area.
• Discover local events
• Save time with handy local services
• Meet new friends at nearby clubs and groups
• Share tips about the area with other local people
• Advertise your local activity

Read more about it here.