I love Montessori.
This sounds crazy, but recently my children have been taking their "SPOTS" (toddler prefolds dyed pretty colors) and making them their "tables." Their name, very clever. No one can bother their "table." It is theirs and theirs alone to work on. They just put it on the floor. Works great. Eventually, it would be nice to get little rugs/fabric pieces that are a little larger. But, even the new 2-year-olds understand not to touch other people's work.