This summer I worked for Clarkson University. I got a research grant for the Physics Department, and spent the summer writing a new laboratory experiment for the Freshman Physics class (PH131).
Basically, the lab is designed to be a more open-ended experiment, involving projectile motion. It is designed to challenge students to model the vertical motion of a dart as it exits from a spring-loaded toy gun. There is no *right* solution, and students will be encouraged to learn at their own pace. This is part of a new "learning trend" at Clarkson that I'm glad to be a part of.
This summer was really a vacation for me

. I didn't have very strict hours, and got to do whatever I want (including trips home, to Battlecry, and to IRI).
Previous 3 summers I have worked as a CAD draftsman. I put in 40-50 hours a week doing engineering/drafting work for a small firm that works in the pulp&paper industry. (I spent a lot of time measuring up/drawing equipment in paper-mills.) It was a lot of fun, and I learned a lot.
Before that...
yeah... I lifeguarded.
Get this guys: They PAY you to sit on the beach and watch the girls! If you don't watch the girls, you don't get paid! It's win/win!
Why am I doing this enginerding thing again? I think I found my dreamjob at age 14....
edit: Someone was whining to me, so I should clarify. I was just joking. Lifeguarding was a lot of fun, but it is a serious job, people put their lives in your hands. It is something to be taken seriously.
/edit