Mostly because it's an extremely difficult problem that pushes me to learn new things across a wide field. If you're interested in checking it out, it's at [1].

I'd like to make something similar to [2] in the mid-term, but the longer goal's to find tickets given in error.

[1] http://github.com/red-bin/chicago_tickets [2] http://toddwschneider.com/posts/analyzing-1-1-billion-nyc-ta...