Treasure hunts are an entertaining and energetic activity for children. Some of the better treasure hunts contain clues or riddles that must be solved in order to progress toward finding the treasure. Many good riddles are appropriate only for certain locations. There is a wide range of examples available online.
Many riddles can be solved within the confines of a backyard. For example, "Go to where the fire gets hot. It's black and metal like a pot" directs children to the barbecue. "What floats from above in a big wind? Rake them in a pile, and then you jump in" directs them to leaves.
Other riddles are more appropriate for a camp setting. Try "Sometimes I'm shallow and sometimes I'm deep. If you jump in, no clothes should you keep" to direct the kids to a swimming pool.
Finally, some riddles are more appropriate for a park. "Don't get buried in these grains mate, or you may face a terrible fate" sends the kids to the sandpit.