The Nova special on the decipherment of the Mayan writing system is now available at their website. It comes recommended from me, for whatever that's worth.
Looking at modern day graffiti, I sometimes wonder what future societies will think when they dig up examples. It will probably take as much effort on the part of archaeologists/linguists as the equally creative Mayan system has taken us. Thankfully, Spanish hasn't completely replaced Mayan languages and the phonetic clues were still available.