GetSimple has always had to deal with complaints that there were not enough good free themes available (and to a lesser extent, plugins). It's been a problem because GetSimple simply does not have the market awareness yet to attract the type of quality files that WordPress and the other larger CMS's do. The March Create-a-thon contest was created as a bold attempt to change this.
FormStack - An easy way to create powerful forms for surveys, registrations, lead generation and more.
BlueCotton - These guys deliver quality Custom t-shirts and embroidery and believe in getting it right with great service & value.
Aside from the specific rules outlined above, the only real way to enter is to start creating and upload your theme or plugin to Extend. if you are familiar with the way WordPress does their themes & plugins, you should have no problem picking this stuff up. If any questions arise on how to do certain things, don't hesitate to ask in the forum...