WebVideoCap allows you to capture videos while your web browser plays them, then save them in a folder to watch later.
WebVideoCap can capture Flash, Windows Media, RTSP streams, MMS streams, and SWF. The video needs to be played in its entirety before you can save it as a video on your hard drive.
As with many apps, you probably want to go through the options before you begin. You can automatically save or ignore different file types, select a download folder, auto-open, filename prefix, select your network adapter, select capture method, and a few other settings in the advanced section.
WebVideoCap has a few known limitations, nothing unusual for an app like this. Most won't see these known issues. WebVideoCap is also portable, but an installer is available.