Scheme is big and small at the same time. It is old, but the last report on the language was released a couple of years back and it is still growing. There is still many areas that needs some love. Checkout http://scheme-lang.com/
You beat me to it!
I'd recommend checking out Chicken Scheme. Not only is it a kick-butt implementation but its community, #chicken on Freenode, is truly fantastic.
Give it a whirl :)