We are definitely always looking for people willing to help out. We have a “beginners” label in our list of GitHub issues specifically designed for developers who want to work on Cesium but are just starting out. Here’s a direct link to a filtered list of them:
You can pick any one of them and start hacking away, but it’s probably a good idea to post a comment on the issue indicating that you are working on it, along with any questions you might have.
We also have a Contributor Guide on our wiki for helping configure your development environement: https://github.com/AnalyticalGraphicsInc/cesium/wiki/Contributor%27s-Guide
The most important thing you’ll need to do is sign and email us the Contributors license agreement (CLA). You can find that information here: https://github.com/AnalyticalGraphicsInc/cesium/blob/master/CONTRIBUTING.md For some reason the CLA links are broken but I’m looking into that now. We can’t take any code from you with a CLA on file.
Finally, while the page may be a little out of day, our GSOC ideas page is here: https://github.com/AnalyticalGraphicsInc/cesium/wiki/Google-Summer-of-Code-Ideas Of course students can also suggest their own ideas as well.
Hope that helps,