If you're a fan of the paranormal and mysteries, you'll want to check out a ghost tour, which is an organized walk where the brave are invited to delve into the secrets of a particular area's haunted past. These tours are run by organizations across the world, whose trained guides will lead you--typically on foot--across a trail of locations, stopping to tell spooky stories at each spot.
In the United States, ghost tours operate out of places such as Galveston, Texas, where a slain police officer is said to haunt a bank, and Parkersburg, West Virginia, where ghouls and banshees stalk the night.
Across the water in the United Kingdom, cities with rich and bloody histories such as York run regular ghost tours, where visitors are taken through the city's eerie passageways.
Geocaching is an outdoor hobby accessible to anyone with a global positioning system (GPS)-enabled device such as those found on many cell phones. Participants attempt to find containers hidden by other players in towns or in the countryside, using their GPS devices to access a list of caches hidden locally.
Each cache is given an entry when placed on geocaching websites. Typically these entries consist of co-ordinates to the cache's location and a cryptic clue for finding it. Once found, players can open the container, but must then replace it so others can find it. Geocaching is usually a very low-cost activity, since caches are often accessible even to those on foot, and the hobby appeals to people of all ages.
A beach trip may sound a little mundane, but you can spice it up by bringing food as well as equipment to make a campfire and sleep out under the stars. You'll want to find out if this kind of activity is permitted first by checking with the local authorities regulating the beach.
Gowalla is a social networking website that creates so-called Spots that are spread around cities, which users visit by logging onto Gowalla's mobile application. When a user visits a Spot, she can check in and access the information, advice and photos left by other Gowalla users at that location.
Lists of Spots are put together by Gowalla fans and organizations, and are termed Trips. You could base a whole adventure around following one of these themed trips. For example, "The Washington Post" has created a Trip that's based on the best burger bars in Washington, D.C.