Yesterday, John Lam announced the first source code drop of IronRuby on his blog. People took it an ran with it, including Scott Guthrie who made a neat WPF sample.
For those not aware, John Lam works for Microsoft, so it may seem a little strange to see it released like that. Jason Zander has a post explaining a little more the roadmap the team is following.
Congrats guys! I hope to play with it more when I get back from Seattle next week.