Last year I bought some acorns just like these at a shop in Venice. The gal didn't know who made them and I needed more so I got busy figuring out "how to". The project expanded to include the hands of my kids, and the afternoon whiled away.
This craft can be changed easily to place setting markers by adding a few things: attach a brown cord to the acorn top and glue it to a twig. Wrap the cord many times. Pick up mini-chalkboards at your local craft store and attach those to the twigs. Assign seats with chalk and voila! Instantly original, fun and homemade. Then, sit down and eat!