Hi Unnikrishnan,
Thanks for your interest. For ideas, a good place to start is our Google Summer of Code
Ideas List. These are pretty well defined projects. If you are interested in something more open-ended, you can browse the
roadmap or propose something completely original based on your interest and background. The projects on the ideas list has contact info for the mentors, you are welcome to reach out to them directly or discuss here on the mailing list since we try to keep everything public. Given your experience with C# and Java, you may be interested in poking around the
czml-writer project.
Also, we can't select applicants until May when Google Summer of Code allows us, but we are happy to work with you regardless of how the GSoC selection process works out.
Regards,
Patrick