If you know how to add an image URL to your advertisement blocker, then to get rid of the forum background, this is the URL to use
http://media5.wgt.com/assets/community/images/wgt/bg/*.jpg?0.55.5016.30801_1016
Apparently there are 8 different backgrounds so you could try using the URL above with the asterisk as a wildcard or you could put in the URL 8 times and substitute the asterisk with the number 1 through to 8 for each different background.