There is a thread on the Wetcanvas.com "Artwork From Life" forum called the Scavenger Hunt. It's been going on, well, almost forever. I join in sometimes, but haven't for a long time. I needed a motivational boost to start sketching regularly again, so I started a few days ago on the current "list". There are 26 items, and you can sketch all, or as many as you can. I'm only posting a couple of pages here. It's an interesting list, but I don't have easy access to all of the items, so I probably won't finish all 26. But never fear, a new list will be out soon.