FIRST Robotics Competition
I'm on the first team from Nebraska, and this was our rookie year. We just finished up our regional competition in Kansas City, MO, and it was a blast. It is one of the only programs that I have found that encourages involvement in science and technology. The build process is almost similar to an engineering internship.
If you happen to be in high school (or not yet there) or you are a professional engineer, electrician, programmer, or hobbyist (basically anyone who uses Instructables!), I strongly encourage you to get involved. Find a team in your area and contact them. There are over 2000 teams in the country, so there may be one near you.
If you are already involved, let me know! I am interested in hearing what people have to say.