From now until the 26th, students and mentoring organizations come together to discuss project ideas, so take this time to introduce yourself, get to know the community, discuss your ideas with us, fix bugs, file some patches and show us how excited you are about coding the summer away!
As usual, project ideas and rules are available on our GSoC page. The ideas list has been updated recently, so don't be surprised if some things have moved around or disappeared. Feel free to choose one or more ideas from that page, or tell us about your own awesome idea!
Our mailing lists should be your first stop. Mono devs can generally be found in the mono or mono-devel mailing lists. There's also the monodevelop-devel mailing list for MD development, and you can reach the docs team for Orchard-related projects in the mono-docs list. There are many more lists, you can find a full breakdown of all the Mono mailing lists here. For external projects, you should also contact the developers in their project mailing lists.
And, of course, IRC is where everyone is, in the irc.gnome.org server. There's the #mono channel, for general Mono discussions, #monodev for Mono development, #monodevelop for, well, MonoDevelop, and #monosoc for GSoC-specific questions and saying hi to your fellow students.
If you're interested in mentoring, send an email to the Mono GSoC administrator at firstname.lastname@example.org.