Speak of the devil and she shall appear. I actually wrote about this (http://www.underdevelopmentlaw.com/2008/03/using-an-eula.html
) a while back. Generally speaking it's always a bit dangerous to rely entirely on another site's EULA. Those were mostly drafted by attorneys who probably knew their specific client's needs. Also bear in mind that an EULA is useful only to the extent that you are willing to enforce it.
That being said, some things to keep in mind/talk to your lawyer about:
1) protecting your IP, including preventing others from unlawfully distributing or reproducing your code/graphics/etc.;
2) including a license to use the UGC of others for promotional purposes;
3) limitation of liability;
4) obviously, the limitations and permissions of the license you're granting for use of your website/game;
5) retention of rights by the user as to their own level design, etc.