Well, You watch youtube videos but your connection is bit slow. So what you can do is search your video and play it. Once the play starts, pause it. So the video will be downloaded (cached) to ur local machine in temporary file. Once the play Line becomes complete red (Completely downloaded), You can play it and watch it.
Now you wanted to play the same video again and u don't want to wait..Simple ..There are various methods to get the video to ur machine and play using ur own player (Say mplayer, vlc, realplay..)
1. You can download Realplayer10, which have options to save youtube videos. (In windows, it works great)
2. There are several tools available, to download youtube video. Grab one and download (Works fine in Windows)
3. If u have Linux Desktop, There is easiest method. (The same may be true in Windows..I don't use windows..Well almost]
a. After pause let the video get downloaded completely.
b. Go to /tmp [cd /tmp]
c. type "ls -ltr' which will sort the files in modified time, so ur video will come in last. The video name will be something like this FlashkqgXus.
d. Copy this file to ur directory [cp FlashkqgXus /home/downloads/youtube1]
e. Now play this video any time using ur favorite player.
My setup is, Suse Linux Desktop, Firefox 1.5, VLC ..