Blackboard isn't all bad—fixing many of its inadequacies was one of my first big side projects in high school.

There was one Blackboard dashboard unit that allowed you to embed arbitrary HTML, and I injected some JS onto the page that allowed you to set a background image, made clicking on links pop open new tabs (instead of whatever abomination of javascript they had), and all kinds of other little tweaks. I even got most of the way through writing a drag-and-drop module rearranger before I graduated. Maybe 60% of what I knew about JS and CSS at the time I learned through trying to add features to Blackboard through script injection.

Naturally, I wasn't the only one frustrated at Blackboard, and the script travelled by word-of-mouth to a pretty sizable chunk of the school. At that point, it was probably the most widely-used thing I'd ever built.