I wrote about CommonSpace about a month ago on the blog(here), and they are still looking for as much feedback as they can get to improve it before it is officially launched.
CommonSpace personalizes an adventure on the town by enabling you to discover places you can reach by walking, biking, or public transit, add destination to an interactive map, and share it with others. Search attractions in dining, drinks and the arts. It utilizes Google Maps and then sites like Yelp or Sustainable Business Network to find cool things for you to do.
My previous blog post as more info, and of course please visit their website- it is a great idea, and they are looking for feedback.