How annoying is that overheating message, eh? I aim to smash it into oblivion with this. Takes a 40 mm fan. Mine is a USB powered one with a speed selector, cheap but functional.

There's two small loops on the sides if you want or need to hold it in place, the idea is to use an elastic band with the... things that holds the headset's elastic bands? Eh, you'll see what I mean.

I tested it by bringing the battery down to 10% then plugging the power and doing all sorts of things: gaming while streaming the video, watching a movie via Virtual Desktop with everything maxed (and boost clock enabled, that likes to pop the temperature warning) but it kept things cool enough. Overall I'm quite satisfied by the results.

Two files, the "logo" one has the Oculus logo, the other does not.