A few months ago we were hosting a little get-together at our place and we ran out of coasters. As we quickly scanned the room for a replacement that was a little more aesthetically pleasing than, say, an old newspaper, our eyes fell on a square glass tile sample. It worked out so well that we ended up going through all of our square tile samples and picking out the ones we liked, and now we pretty much exclusively use tile samples for coasters. The one above is from the Angela Adams collection at Ann Sacks!
We really like our newest use for are otherwise "get back in that box and stay there until I need to source you" tiles. They're free, they're cool looking, and most importantly, they work really well.