Lazy Loading Responsive Adsense Ads
This is a nifty tutorial showing how to make your current adsense ads responsive and lazy loaded. Immediately I thought “this has to be against the terms of service” and people mentioned such in the comments, however it seems as though the rules have relaxed since last I looked.

The nature of Google Adsense is that the ads, along with the script, file are loaded automatically: this may unreasonably slow down the appearance of the other important things, like styles, fonts, or other scripts.
An excerpt from Lazy Loading Responsive Adsense Ads