It is not necessarily a RAR archive and in this case probably isn't.
Open the first part "the hand struck three on the 4th clock.avi.000" in Notepad, if the first four characters are
Rar! then it is a RAR archive and you can open it via WinRAR's
Extract To button. If the first four characters are
RIFF then it's a split AVI and is not compressed but merely an AVI cut up into pieces, a file joining tool like
HJSplit will let you put it back together quickly and easily.
For more info on actually using Usenet binary groups take a look at
Slyck's Guide to The News Groups.