One of our favourite games is a game my older kids and I made up when they were younger.  We call it “The Money Game”, for lack of anything better.  We basically get out our bucket of loose change, divide it randomly into piles in front of each player and then offer fair deals to one another.  “I’ll trade you two dimes and a nickle for a quarter.”  If it is a fair deal we trade, if it isn’t we suggest what a fair deal might be.  Sometimes to switch things up a bit we try to get the most or least number of coins possible in our pile, or see how many different ways we can come up with a dollar.  It’s a simple game, but easy and effective….and most importantly the kids love it.  I can’t say I understand why, but suspect it might just be their fascination with money or the hands on nature of the game.  In any case it really doesn’t matter as it gives them a reason to count, skip count, and add.