Many many years ago, I picked up 8 pieces of really thick glass at a garage sale. They are the size of a dinner placemat. So I use them for.....you guessed it....placemats. I LOVE these things. You can put whatever you like under them to fit whatever theme you like. I also got 8 that fit a round table. (the whole works for 2 bucks. The edges are rounded and smooth.
I stick autumn leaves under them for Thanksgiving. Christmas cards or pics at Christmas. Print off different pictures of the guest of honour.....birthday boy or whoever. Sometimes I've used some interesting clips or funny stories just to read....sprinkle some confetti....etc. For kids, you can put in search and find pics to keep them amused. (a lot of this stuff printed off the computer) Well you get the picture.....the ideas are endless. (even just cut up shapes of coloured paper or pretty pics from thrift store magazines. You can even make some very elegant settings)
Anyways....the point being.....they're wipeable. No placemats to wash, and your tablecloth gets many more than one use. Best 2 bucks I ever spent.