We have done scavenger hunts mostly while traveling. If we are ever somewhere where there is some down time or we need something to do, we can usually brainstorm a scavenger hunt to fit our situation. When the kids were younger, we would even do them around the house.
While we were camping last week, my husband went for more ice so me and the kids came up with a scavenger hunt to pass the time. We made a list of about ten items that we thought we could find, but too easily. As my kids are older, we all went our seperate ways, each armed with a list and a baggie to collect our items. It was great fun to see even the teenager get in on the hunt. We allowed thirty minutes for the hunt, then met back at our camp site to compare our findings.
You can create a scavenger hunt to fit just about any locale you find yourself in. Even if you are stuck in an airport, or waiting in a doctor's office. You don't necessarily have to make your list items that you can tangibly collect. You could look for items in your surrounding (for example, someone in a green shirt, a comic from a magazine, a seeing eye dog, etc) or you could make it for items that might be in your purse or bag. Be creative. This is always a fun way to pass some time together.