Can anyone get me a Code for a Cool Background for my UserPage?
Or Just a plain black code...

Well according to the VMK wiki page about userpages this is what I found about it.
If you would like to have an image as the background to your page, then the following is what you need.

<table border=0 background="image link" width=100%>
<tr><td>
CONTENT HERE
</td></tr></table>
Remember to change the area in bold to the link to your image file, this has to be hosted somewhere.

I suggest starting an account on photobucket, but if you don't want to start an account, imageshack works.