The same ad spaces that shouted about insurance and laundry detergent last week now contain nothing but fluffy cats, as an art collective uses the internet’s number-one obsession to temporarily transform the London Tube system. The Citizens Advertising Takeover Service (CATS) is the result of a Kickstarter campaign by brand-new collective Glimpse aiming to “create a rip in the space time continuum.”

The group raised enough money to buy all of the ad spaces in the Clapham Common station – a total of 68 – for a two-week period, and the new posters feature cats from the Battersea Dogs and Cats Home and the Cats Protection charity. The organizers are careful to note that they’re not against advertising per se, but rather hope that the project will “inspire people to think differently about the world and realize they have the power to change it.”

But the broader point – and appeal – of CATS is the citizen takeover of public spaces, with everyday people getting to decide what they want to look at as they navigate their cities. Wouldn’t you rather be surrounded by what essentially functions as an ad for animal rescue services than dozens of posters pushing a bunch of junk corporations want you to purchase?

“Back in February we asked ourselves to ‘imagine a world where friends and experiences were more valuable than stuff you can buy,’” says Glimpse founder James Turner in a post on Medium. “The team began thinking about crowdfunding to replace Tube adverts with something else. Beautiful forests? Time spent with family? Hmmm. We wanted this to become famous, so we needed something the internet would love. Frame it that way and the answer’s obvious. Cats.”

“We’ve been on the news in China, and one of our backers is flying in from America to see his cat in one of the final posters. This project has uncorked a kind of energy that I haven’t experienced before. When you talk about CATS, eyes light up and new ideas start to flow. We don’t know exactly how Glimpse is going to work, but we want to carry this energy with us as we grow up.”

It’s a wonder nobody crashed their real cars doing a double-take at a glowing Audi that seems like an apparition, appearing in a fog and then disappearing just as quickly. German ad firm Thjnk came up with this ephemeral ad campaign for the hybrid-electric Audi A7 Sportback h-tron quattro to highlight the fact that nothing but water vapor comes out of its exhaust.

“We asked ourselves, where do you place ads for the most environmentally friendly and progressive engine Audi has ever built? Nowhere. So for the car that leaves nothing behind but vaporized water, we created ads that leave nothing behind but vaporized water.”

Though the agency doesn’t specify how the effect was achieved, it seems that an LED image is projected onto water vapor to get that ghostly look. The ads were placed in busy areas of big cities at night, flashing briefly and then vanishing.

Check out 300+ other creative advertising campaigns, from guerrilla marketing to controversial ads using revolting imagery and graphic content to hawk hand soap, nose trimmers and other products and services.

(Check out our complete collection of Subversive Marketing and Culture Jamming.)

Subvertisements are an excellent means of turning the commercial world around you upside down, make humorous or critical commentaries on consumer society, or even get rid of ads altogether. Subvertising can sneak up on you, entertain you, and possibly lead to premature enlightenment. Get started by removing those pesky ads that always pop up while you’re surfing the web – or better yet, replace them with the creative works of up-and-coming artists:

AddArt is a FireFox extension that automatically substitutes artwork where you’d normally see banner ads. Currently, AddArt is in development but you can get AdBlock which at least pastes over ads with a neutral color. Subvert your web browser and skip the adverts you never click anyway.

Blocking or replacing ads with art are both well and good, but with a little Photoshop work you make your own public service subvertisement on a subject of your choice. This series of well-rendered Aboslut ad spoofs is definitely double-take material.

Alternatively, take things a step further: issues of global equality and health are fair game too. The tag on the left is a none-to-subtle reminder of the origins of so many clothing products in sweat shops. On the right, the McDonalds logo is neatly transformed into a harbinger of death – you won’t see that on their commercials.

OK, so enough fun and games online: you can also just go right out and start editing advertisements and billboards on their own turf. Take down a major auto manufacturer by adding a few words, or cover up a pair to make a point about SONY. Subvertising in public can be complex and thought out, or might simply take advantage of what is already out there.

Editing not enough for you? Well, here we start getting into some serious territory, but: you can also follow these step by step instructions on how to take down a billboard altogether. Watch for the ‘danger zones’ and don’t get squashed in the process. Otherwise, check out a site with good links to further resources and more basics about subvertising.