The Ubuntu project applied as a mentoring organisation for Google Summer of Code 2011, but unfortunately we received the following reply:

Unfortunately, we were unable to accept your organization's 
application at this time. We received many more applications for 
the program than we are able to accommodate, and we would 
encourage you to reapply for future instances of the program.

The announcement of the accepted mentoring organisations says that of 417 applications, 175 were chosen, 50 of which are new to Google Summer of Code. All the best to the mentoring organisations, mentors and students of this year.

Even if you can’t participate as part of Ubuntu in GSoC2011, there’s loads of great projects part of it this time, just bear the time-line in mind. Good luck!