I did a similar thing my freshman year of college, and by junior year I created an API based around the class registration system and an iPhone/Android app for

I did a similar thing my freshman year of college, and by junior year I created an API based around the class registration system and an iPhone/Android app for it that sends push notifications to students when the class they want opens up (shameless plug: http://www.eaglescribe.com/ http://www.eaglescribe.com/). This past semester, the active users was between 1/3-1/2 of the undergrad students in the school. As you can imagine, popular classes had dozens of people "subscribed" to receive notifications when it opened, so it became a race to sign up once the push went out. On the plus side, this gave us a treasure trove of data on the most popular courses, and we've been in communication with the school to see if they would be interested in this data.