Google Videos will allow you to "lock" a rental to your tablet to view offline. My personal experience is that you need to plan ahead for this. I tried to dl a movie while waiting at the gate for a flight to board, and it never finished loading. When I got home, I was able to dl it via my personal wifi, but that still took a long time. It played back just as expected when I had it downloaded, though. I'll use this again in the future.