You could make a simple framed square or square in a square or a 9-patch with the center block/row larger for more writing area, then back the area where you want the writing with freezer paper, or use the manila folder method I posted in another thread. Then people would know that the writing should be in a very specific area. And, as PaperPrincess said, have someone monitoring the table where the blocks are. In fact, make sure she has a comfy chair and something delicious to drink. Someone who knows everyone and loves to visit is perfect for this, because she enjoys talking to everyone.