I'm still in college and I enjoy building stuff. The quickest way to bore me is to read through my textbooks without doing actually coding anything. It's fulfilling to build things that solve real world problems, which is why I want to either sign up for coding competitions that will challenge me to get better quickly or spend time contributing to open source projects. Which one is better for a college student who wants to learn skills for real world problems?
In my opinion, coding competitions are the better path for a college student. - It's a competition, so there is pressure to do something better. - Your thing will have to be completed in a short amount of time. This allows for you to not disrupt possible college priorities. - You might just come up with something cool, and launch something new. - I believe that these achievements could reflect better on your resume, as well as create interest (more so than open source).
Cheers, and good luckKevin