Firefox: If you’d like to save a video you’ve found on a popular streaming video site, NetVideoHunter is a handy Firefox extension that makes that download a snap.
Most extensions and add-ons enabling video downloading usually place a single link by the Flash video box on certain sites, letting you download the file you’re currently watching. NetVideoHunter places a small icon in the lower right corner of your browser, tracking the videos you’ve watched.
Clicking on that icon will bring up a list of videos, including the current one you’re watching. From that list you can download or play the files. The ability to grab previously viewed videos is rather handy if you’ve decided, after tunneling through a YouTube chain, that you’d like a copy of that video three clicks back. It works on nearly any video sharing site including YouTube, Google Video, Metacafe and Dailymotion.
NetVideoHunter is free and works wherever Firefox does.
It’s easy to forget these days that the internet started out as a place for academics and researchers to trade data and knowledge. Recapture the web’s brain-expanding potential with these free resources for educating yourself online.
Coding, whether on the web or on the desktop, is one of those skills you’ll almost never regret having. Coincidentally, the web is full of people willing to teach, and show off, programming skills. Whether you’re looking to knock out a modest 
“MBA programs don’t have a monopoly on advanced business knowledge: you can teach yourself everything you need to know to succeed in life and at work.” The 
Nobody’s pretending you can talk like a local without some immersion experience. But there’s a lot of resources on the web for honing an already-sharpened second language, or at least picking up some of the vocab and nuances. 
As Ramit Sethi put it in 
We have to guess that having a giant, searchable database of free academic lectures was just too good an idea for two different web firms to pass up. Academic Earth has been described as a Hulu-like aggregator for lots of major universities’ content, and offers the slicker and more navigable front-end for them, as well as allowing embedding and sharing with no restrictions. YouTube EDU might have a broader reach, and the player and format might be a bit more familiar to most. Both sites offer both individual lectures and full course series, and are definitely worth checking out.
Sites like 
If being dropped off at the music store/mall/piano teacher’s house wasn’t a memorable part of your childhood, you might dig the digital age’s equivalents a lot more. Guitar players, in particular, have a lot of places to turn for video, audio, and graphical teaching tools. Adam rounded a lot of them up in his guide to 
A huge number of colleges, universities, and other degree-granting universities are going all open-source these days—giving away the actual guts of their courses, while retaining their revenue stream by awarding degrees only to those who pay. In this day and age, though, programming, marketing, design, and other self-taught skills are pretty valuable, however you came by them. Whether you're looking to break into a field or just augment your skill set, dig into our guide to 
Web site Academic Earth is like Hulu for academic lectures, pulling free lectures from Berkeley, Harvard, MIT, Princeton, Stanford, and Yale into one attractive, easy to navigate site. It’s incredible.
Windows/Linux: Elisa 
Windows only: Sure, almost all the offerings on NBC Direct can be watched at streaming site Hulu. But if you’re an HD fiend and want offline access, NBC Direct’s player might be worth checking out.
Once the installation starts rolling, you’ll be asked to close down your browser. NBC Direct downloads and plays its shows through your browser, and it plugs in a rights-restricted media handler to do so (pictured at right).
Even when you’re “offline” to watch a show, though, you’re getting some ads. The one complaint I’d make about NBC’s video site, versus Hulu, is that they take “fullscreen” to mean something less than literal. Here’s an episode of The Office, in HD, set to “Fullscreen.” There’s actually a bunch more space at the bottom and right-hand side, but I clipped it for Lifehacker page constraints:
If you’re a frequent viewer of Netflix’s streaming fare, you’re probably numb to how inefficient the rental service’s browsing and search pages can be. InstantWatcher is a soothing balm of clean, fast movie browsing.
Browser cache locating utility VideoCacheView searches through your browser cache for already-watched videos—so you can copy them to your videos folder.
YouTube has made it easy for anyone to easily download clips as MP4 video files, if a creator allows it, as well as purchase the videos you want to bring with you.