This idea popped into my head as I was looking at my own personal odd thing and thought it'd make a good thread topic.
At first I thought maps were odd, but I bet a lot of people keep the maps for comparisons, memory etc.
So my next thing is bags, as in the bags they give you in the gift shops. I kept them from my trip, and not just to keep my stuff in on the way home. I kept them as souvenirs and they will stay with the rest of my souvenirs.
So what's yours?