We picked up a neat toy for our kids - a marble run set. It's a bunch of connectable pieces that build into a track for marbles to follow down. There are wheels to spin, bells to ring, and whirlpools to descend. I think the best games require kids to be creative, and this fits the bill. They keep coming back again and again to build new tracts. So far our tallest tract was nearly 5 feet tall.