For my friend's 13th birthday, me and my friend had a mall scavenger hunt for my best friend.  When all the guests arrived, we gave each guest a candy bar(mini Hershey bars work great for this).  Under the wrappers put a different color piece of paper;ex:if there are 16 guests put like red, yellow, green, and, blue put four of each color under a wrapper). That way the teams can be equal.  Then we made a list of like 60 items. Each group got an older person as their "leader", a camera, and a watch.  The camera was used to take pictures of the items on the list to prove the groups found the items. And the watch is used to keep track of time, because you only get a limited amount of time to find all the objects on the list.  Then we picked the mall to have the scavenger hunt at and and started the scavenger hunt.  Now the rules were: you had to stay inside the mall and every three minutes your team was late to the finishing point after three hrs. an object was deducted that the group took a picture of.  I hope that you pick to have a mall scavenger hunt and have as much FUN as we did!!:-)