Not every airline offers 'in-flight' entertainment. Hopefully, you'll be on a flight whose in-flight entertainment works, unlike my trip to Japan... :( Try flying 15 hours without being able to use the in-flight entertainment system due to server errors...spend hours staring at code scrolling by, next to a little Linux penguin...you can read about THAT experience in this blog post.

Alaska Airlines offers a portable device that you can buy for $10, called the 'Dig-E' player. It's very worth it if you're flying for a long time- say over 4 hours. I always get one when I fly to Seattle from Orlando (it's 7 hours of bumpy terror, so I like to have a little comedy to watch/listen to). The players come preloaded with movies, tv shows, music, documentaries, and even commercials.

Last time, I watched a program on the world's best commercials of 2007- it was great and made the time pass by really quickly. The players aren't finicky when it comes to headphones, so you can plug in your own fancy ones that block out noise, if you want. Sweetness!