Once again Yahoo! is opening its doors to a horde of unwashed hackers. You should join us!

In case you missed last years Beck-filled extravaganza, Open Hack Day gives developers 24 hours to build a cool hack and demonstrate it to a packed audience and celebrity judges.

Better yet, some of the Flickr staffers will be on hand to answer any of your burning API questions and judge the Best Flickr Hack category (and yes, there are prizes).

Open Hack Day kicks off Friday with talks on Yahoo! APIs and technologies. Flickr-related talks include:

• Getting Started with the Flickr API – Friday, Sept. 12 from 11:00am to 11:50am
• Building a Purple Pedal GPS-Flickr Bike – Friday, Sept. 12 from 12:00pm to 12:50pm

It runs from Friday, Sept. 12 to Saturday, Sept. 13, at Yahoo! HQ in Sunnyvale, CA. If you’re interested, go to the Open Hack Day website to register.