The second picture is the main menu which has an a new icon; Get involved aka STK contributions. I am not very good with Gimp, so the five icons are not evenly spaced.
Clicking "Get involved" takes you to a new tabbed window (the first picture). Each includes a brief explanation about how STK is made by a company, but a team working for free and by volunteer contributors. Another option would be the first tabbed window that is open is the explanation about STK development, the team, and about the other windows that would encourage people to look around. The sections for contributions (that I could think of) are; Art (blender icon), SFX and voice acting (music note), Level Design (track), Programming (the tab that's opened in the window), and Quality assurance (bugtesting, helping solve problems on the forums, keeping wiki things updated, writing tutorials, making high def trailers and playthroughs, etc). At the bottom of the page you'll see the button now takes the person to the STK website (the relevant section of the website for each different contribution). In retrospect I should have include a "donations" tab. Let me know what you think. We could recommend other FOSS programs that can be used for the art and sfx categories.
The wording is a little heavy handed, but you get the idea. Anyone who downloads the game can understand more about how it is made and that they can help improve it. We could have check marks for accomplished tasks and then parenthesis with a (thanks TuxFan37). That way volunteers are rewarded with recognition.