Google Summer of Code
Google and I have participated in a series of long-term engagements around their open source programs, particularly Google Summer of Code and Google Code-In, which are both ways Google rewards students for contributing to open source projects.
Google Summer of Code changes its logo every year, and approached me to create the logo for its 2012 season. The GSoC team listed several key concepts they wanted the logo to touch on. They wanted to show that the program is a social one, that it's international in scope, and that it's primarily about programming. There wasn't a desire to make it too much about the weather of summer, as of course for their southern hemisphere participants, it wouldn't make much sense. They also needed the logo to be flexible in dimensions and print nicely in 1-color.
I picked a collection of flags, waving on a clear day - the variety of shapes and colors suggested internationality, and the angle and positions of the flags suggested they weren't simply stuck in the ground, they were being held — a way to drive home the people-centric and social nature of the program. Another advantage of the flags is that they can be rearranged to fit any space (for example, social network avatars) and still retain brand identity:
For 2013's class I was asked to make a slight tweak to the logo, so I changed the background flags to balloons: