We've developed our own custom software for the tablets that lets us to do many cool things.
For example, we limit student access to only pre-approved content so that when someone is using the device, we know that they are learning. The software also organizes content into lesson paths that are easy for students to work through independently. And we can control which games go on the device – limiting them to ones with educational value, and setting them up to be unlocked for short periods to reward kids for completing assigned tasks.
Our software is also designed for synchronization and analytics: when devices connect to the Internet (say, once a month) our system updates the content on the tablets and collects anonymous analytics data on how devices have been used, so we can monitor progress and keep improving our projects.