So far this has happened twice to me, once while playing CS:S, and once today while playing TF2. You can kinda see the weird shapes that appeared on my screen in my picture, except in game they covered the entire screen. Is this maybe the GPU overheating? (I added the red circles afterwards btw)
Could it be a problem with geektool?
edit: btw, it was fine after a restart
Could it be a problem with geektool?

edit: btw, it was fine after a restart