I have, Who Has? Students are each given a card with an amount of money displayed. Students count the money on their card and then a kind of "around the world" is played. I like to time my students (the first time is painful) - students keep the same cards and play again. I've used this game in many different ways (multiplication, base-10 blocks, etc)
Skyping with other classrooms - this page has been set up to help you make connections with classes in other countries who are interested in having Skype conversations with other classes.
I used this in my math class, with students who were struggling to tell time to the minute. I used the "Stop the Clock" 1 minute intervals, but there's lots of good things on this site!