Hedgewars – free multi-platform game similar to Worms
If you were born in a generation where Worms was considered a near equivalent to Mario, then you might want to check Hedgewars. It's basically the same game except that you are not a worm and it works great in most platforms. Old versions of the Worms game won't work at all on Vista and most of the current systems today.
Even though it's essentially a Worms clone, it is awesome. It features really smooth gameplay and graphics are pretty good. Plus, it will definitely give players a great time.