This form will bypass the normal "Edit Profile" part under the user cp and reset your signature. Unfortunately it will also reset your biography, AOL, ICQ info and so on (that is, everything in the "Edit Profile" part of the user cp except for the username, email and password) but you can retype that info later without problems.
As e-mail, username and password are required information to update your profile (security reasons), you have to provide this in the form otherwise the database won't update.
<table border=2><tr><td><font color="#FFFFCC">
<form action="http://enworld.cyberstreet.com/member.php" method="post">
Username: <input type="text" name="username" size="20"><br>
Password: <input type="password" name="password" size="20"><br>
E-mail (same e-mail as in the user cp): <input type="text" name="email" size="20"><br>
E-mail again (same e-mail as in the user cp): <input type="text" name="emailconfirm" size="20"><br>
New signature: <input type="text" name="signature" value="Psionicist is my best friend!!"><br>
<input type="hidden" name="action" value="updateprofile">
<input type="submit" value="Remove my ENWorld signature now.">
</form></font>
</td></tr></table>
I tried it myself. Check my signature.
Edit: Please quote this message to view the source code. Your info will never leave the ENWorld server.
Edit2: Nuts, this thing is highly addicitive. I have reset my signature a dozen times now.
