The other day as I was cleaning I came across some inserts from chocolate boxes that were laying around leftover from the holidays. As I was getting ready to toss them in the garbage I thought maybe LK would like to play with them for a while. I got out our jar of buttons and poured them on a jelly roll pan (using it as a tray to keep the buttons somewhat contained). Then I had him sort the buttons into the chocolate insert. It kept him occupied for a little while and while he wasn't all that interested in sorting them he would find matching buttons and put them together.
Of course, buttons are a choking hazard, so if you do this be sure to supervise your child.