Do you sweat like a hog, making your mouse totally slippery and near-unusable? Well the Mouseblisters are designed to stop that from happening while also making your mouse look really ugly.
The little stick-on nubbins soak up all your sweat, keeping your mouse from becoming a slippery little puck. They also increase its size if you have big hands, and apparently help reduce RSI. But really, they just make your mouse look stupid. As long as you're OK with that, go nuts.