Android: PAUL is a handy app that downloads videos from your favourite news sources and social networks in the background, and lets you watch them all in one place.
PAUL could be best thought of it as a smart podcatcher for video. You can subscribe to various video services, including YouTube, ESPN, and CNN, and also connect your social networks to download videos posted by your friends. The app will learn your preferences over time, and adjust its algorithms to download the most relevant content, and a variety of included home screen widgets will keep you updated on the latest videos available.
The app also provides some fine-grained controls like specifying how many videos PAUL should download for each channel, and how long they should stay cached. PAUL will only download videos over Wi-Fi, so you can also specify what times of day you're usually connected.
If you want to stash some great video for offline viewing, and access it all in one place, PAUL is a great resource. Best of all, it's available for free on Google Play.