What an excellent concept for a web site: users review and rank different experiences around the world and encourage others to do the same.
Activities range from run-of-the-mill (food/drink recommendations) to the more adventurous: travel/sightseeing and the great outdoors. Visitors check off stuff they've done, highlight things they want to do, share stories about their unique experiences; and in the process, can meet people and join groups with similar interests.
Seriously, where was this site when I was single?