Libra

Go to activity and hover over it until My Activity Streams appears, click the little drop arrow to make a drop down list, go to create new streams. Name it what you want.. I made one called "No Debate Pit".

Play with any fields that interest you, but for debate pit... under Content Types checkbox topics, click the little arrow to the right of it and then click EVERY forum you DO WANT TO SEE, make sure they are highlighted grey with a check. When done, save it... it will now appear under your custom streams. My test one will show me every new topic not debate pit that shows up. You just have to remember to go to your custom stream each visit and not just click activity.

I tried that, and now its only showing me topics from that section, and it doesn't show my "click here to black out posts from this topic"

Go to activity, my activity streams, then click whatever stream you created and then edit it... make sure you save any changes off to the top right by clicking the save button. Just play around with it. If you explore all the options you can do all sorts of things with it. I have mine set to remove debate pit, role-play and the other forums I never bother with.