Imagine a plugin/widget that enabled a DVR to replace ads in a program with ads from a different decade - of your choosing.
I thought of this while watching the original V miniseries on SyFy. It's from the early/mid 80s. The hair, clothes, special effects, everything is awesome. Then I thought - imagine if, instead of the crappy Levitra ads or whatever garbage is showing now, they showed commercials from the 80s that are roughly in time with the show's original airing? How cool would it be to see a Members Only ad, or a Kool-Aid ad with the giant pitcher of Kool-Aid, or one of the original Nest-e Plunge ads, or a Sunkist ad from the 80s! That would be awesome! I'd actually pay attention to the commercials just for the kitch factor.
From a business perspective, it'd be hard because you'd need to obtain the commercials from the early 80s. I have no idea if those ads are laying around in some storehouse or not. And, if they are, would the companies allow you to use them? Maybe... It's cool brand advertising for long-lived brands. So, maybe they'd pay a similar price for the 80s ad as they would for the modern ads.
From a tech perspective, there are several problems. Assuming you can find the original ads somewhere, you'd have to digitize them for delivery in modern cable signals. This is probably feasible assuming they exist. Also, there's the issue of the set-top box integration. You'd need some way to detect that an ad was about to display, and intercept the display in order to show something else.
I don't think that's possible currently, but I could be wrong.
The UI aspect wouldn't be too hard... at the start of the show, or in a persistent configuration setting you could pop up a small dialog window asking from what decade you want to see ads. Actually, I would love to see ads from the 60s. I'm too old to have ever seen the cigarette commercials on TV, but having seen some clips, they totally rock.
All in all, I doubt this is a viable business, but it would be so cool.