It's easy. If there's a knee-slapping viral video or an NFL highlight reel you've got to own, you can get it with just a little effort. To reduce the risk of legal trouble, don't distribute it, though; keep it only for your personal use.
If you want a clip from a video-sharing site like YouTube or break.com, one super-cinchy way is to plug the URL into KeepVid (keepvid.com). It not only downloads the clip for you but can also convert it into an MP4 file that will run on most video players. Several helper apps can do the job as well. If you're on Firefox, use the Tools menu to install the DownloadHelper add-on, which places a convenient video-capture button right on your browser. Or you can try Miro (free; getmiro.com), an open-source video powerhouse that helps you find, store, and organize clips (including many in high-def) and plays a host of different file types.
If you want to capture live streaming video rather than stored files, you're going to need to spend some money. For Windows, check out SnagIt ($50; techsmith.com) or, on a Mac, Snapz Pro X 2 with Movie Capture ($70; ambrosiasw.com). They'll let you grab anything you see, so you can quickly build up your own video jukebox.
Downloadhelper really is quite good.
also, a handy tool is WM converter 2(download.com), which converts files from .flv (like on youtube) to other more useful formats such as MP4 or MP3 so you can put them on portable devices.
I just use Firefox and the CacheViewer plugin. Once the vid has downloaded fully, search the Cache for the video/flv mime types and copy to disk. Then use a converter like the one njdevil suggests.
you could download CamStudio from Camstudio.org for free for capturing live video.
Several other options I use include vixy.net, mediaconverter.org (or even better, the media converter add-on for Firefox), and vconversion.com
All of these services let you convert to many file formats including mp4, mp3, flv, and wmv.
Firefox has an add-on called unplug that allows me to pull many video sources from websites.
And once you have them now you can convert them anyway you choose to any other output using SUPER www.erightsoft.com/SUPER.html I personally don't like the interface of SUPER, but it has some really mean power, oh and its FREEEEEE.
Does anyone know to capture a video off the comedy central website?