I only have a little bit to add to some great ideas about activities/shows to engage in before law school.
1. Someone mentioned that "The Wire" was recommended to them. YES!--everyone should watch this show. It is amazing. I won't say anything else so as not to spoil the experience for anyone who may actually check it out.
2. Yale Open Courses are incredible, and I recommend sampling topics that are not
law-related. I've found history courses are interesting, and sometimes do touch on historical sources of law and law-making. Political Science courses also are interesting in their own right, and help illuminate much about current law. http://oyc.yale.edu/courses
3. GTM seems like a great book so far (I'm in the midst of reading it). I would recommend it to other 0Ls.
4. Personally, I am also watching TV shows (Arrested Development--goes without saying), gaming, reading, working, and drinking about a liter of coffee per day and anywhere from 1-3 pints of beer per night. Some of this (the coffee and beer, the reading) will persist into and throughout law school; some (probably gaming) will not.