Scavengers were asked to get dates from a building cornerstone and a gravestone, an inscription from a building lintel and a gravestone, to count the number of seats in a restaurant and the number of overhead light standards on a bridge, to identify historic community landmarks, etc. Our church youth group did a Polaroid scavenger hunt once. Ask among your group if anyone has a Polaroid camera they'd be willing to loan. If you divide into 2 or more teams, you need a camera for each team. You make a list of different settings- for example, get a photo of your group doing a human pyramid, a photo of your group in front of a house with the numbers 123, a picture of a member of your group getting frisked by a police officer, etc.
Some pictures are worth more points than others, depending on difficulty of acquiring the picture.
After the time is up, you add up the points. The activity is great fun and the photos afterwards are great souvenirs. Here's a twist on the old scavenger hunt. For a neighborhood block party we had a Service Scavenger Hunt. The first group to meet back at Base with all the items done got a prize.