Tell me I’m not the only mother with a two year old who thinks the best thing to do with five boxes of puzzles is to put them all into one bucket together.  Luckily for me, I learned at a university lab preschool, that it is very handy to number the backs of your puzzle pieces to help out in just such a situation.  Each time I get a new puzzle, I write a number on the box and then write that number on the back of each piece.  Then, say when I find two random puzzle pieces mysteriously stuffed into the only VCR left in our house, I can quickly determine which boxes to return them to.  Now if only fixing the VCR was that easy!