We've opened up Yahoo! from the inside out with our world-renowned Hack Day, and from the outside in through the Yahoo! Developer Network. Now we're opening up Yahoo! itself to a select group of hackers and special guests for a weekend festival of hacking, camping (yes, the tents-in-the-outdoors kind--we have really, really nice grass!), music, and good times.

We'll kick things off on Friday, September 29th with a free all-day developer workshop. Then we'll launch a 24-hour Hack Day with an outdoor party into the wee hours, with special guests providing the soundtrack. (Details to come later, but we guarantee this won't be your usual corporate-wedding-band leading the crowd through 2am group sing-alongs of "Brick House.") We'll hack through the night, keep going through Saturday morning, and wind it all up that evening with hacker demos, judging from a panel of luminaries. and special awards for the coolest hacks. We'll have special guest speakers all weekend, with Michael Arrington of TechCrunch presiding over the festivities. And after nightfall we'll close things out with another round of entertainment that you would be happy to pay for, except that you won't have to.

We have no idea what's going to happen at Hack Day. We never do. We're pretty sure we'll be amazed. We're still working out the final details, but we'll be posting more here soon.

If you'd like to attend, please sign up on Upcoming.org. If you're interested in creating and showing a project at Hack Day, please fill in the form below and we'll be in touch.