These video clips are AVI files, and should be handled automatically by Mac OS X and Windows clients. For Unix systems, the xanim animation player should work, but your browser may not be configured to handle AVI's. To configure your browser to handle AVI files properly, try putting this into your $HOME/.mime.types file:
type=video/x-msvideo \ desc="AVI" \ exts="avi,AVI"and putting this into your $HOME/.mailcap file:
video/x-msvideo; /usr/local/X11/bin/xanim %s >/dev/null 2>&1
If your browser still doesn't know what to do with AVI files, you may have to download the files and then run xanim by hand. In that case, I suggest you download into /tmp. Remember to delete the file after you're done.