Within AdSense, add your own domain to your block list.
Or within AdWords, do the same.
A different take on this same quote... as a marketer and ppc consultant, i often have the need to show clients what their ads i'm running look like (especially click-to-play video ads). On my marketing site, would be great if I could show their ad. I've tried site targeting, but my site isn't relevant to their products cuz it's about mu consulting biz. Perhaps MCC account could have a showcase feature or something similar where we can specify the url / page and have an ad show there that's not tracked for clicks, imps and doesn't even go anywhere (like the ad preview tool).