If you don't ever want to see the Games threads, you can hide that entire section by clicking on Personalize under the Discussions title on the main index page, then by the Games section on the far right of the next page, click on the Yes so it turns into No. Then you'll never see any more Games threads! You can reverse this in the future if yuo change your mind.
Otherwise, you can always mark all the posts in that section as Read - open that section of the forum, scroll to the bottom of the page and click on the More Options link (next to a little cog), then click the Mark All As Read button at the bottom. The problem with this method is it will only work until someone else replies on one of the threads but it will clear most of them off for quite a while for you.