The code for the applet is this:
<applet archive="Rot2.jar" code="Rot2.class" width="256" height="256">
<param name="credits" value="Applet by Fabio Ciucci (www.anfyjava.com)">
<param name="res" value="1">
<param name="image" value="pics/hypnodisc.gif">
<param name="rotmode" value="2">
<param name="rspeed" value="20">
<param name="zoommin" value="4">
<param name="zoommax" value="25">
<param name="zoomspd" value="4">
<param name="modix" value="1">
<param name="modiy" value="2">
<param name="auto1" value="100">
<param name="auto2" value="230">
<param name="distval" value="10">
<param name="tile" value="NO">
<param name="backimage" value="NO">
<param name="backr" value="192">
<param name="backg" value="192">
<param name="backb" value="192">
<param name="overimg" value="NO">
<param name="overimgX" value="0">
<param name="overimgY" value="0">
<param name="textscroll" value="NO">
<param name="regcode" value="bcd-fleruue.mmr-jpoedjmgnpm">
<param name="reglink" value="NO">
<param name="regnewframe" value="NO">
<param name="regframename" value="_blank">
<param name="statusmsg" value="Hypno Disc">
<param name="memdelay" value="1000">
<param name="priority" value="6">
<param name="MinSYNC" value="2">Sorry, your browser doesn't support Java.
</applet>That means you'll need Rot2.jar (http://www.diamond-jim.com/hypnodisc/Rot2.jar) and hypnodisc.gif (http://www.diamond-jim.com/hypnodisc/pics/hypnodisc.gif). Rot2.class is contained within the JAR file.
I'm not sure what the licensing is like on this one, though. The script itself is by AnfyJava (http://anfyteam.com/index.html). They distribute some applets for free, but they also sell some commercially. If it's one of the former, you've no problem with that. Unfortunately, they don't provide a listing of the applets available in each package, so I can't tell.
The image, however, is quite possibly copyrighted to Jim Tyler.
Out of curiosity, do these things actually work, or are you just using it for decorative purposes?