Every year, Los Angeles-based architecture firms build cat shelters to raise money for FixNation: a non-profit organization that aims to reduce stray cat populations through spaying and neutering. While most cats would probably be just as happy with an old cardboard box, the project provides an opportunity to see architects have some fun with designs for a good cause.

The Giving Shelter event was conceived by Architects for Animals and held in Culver City, California, on October 19. It includes 12 firms, such as HOK and Perkins + Will, and a total of 13 shelters.

The shelters are currently up for auction, along with 28 cat food bowls decorated by big name celebrity cat enthusiasts like Jay Leno, Charlize Theron, William Shatner, and Clint Eastwood. Head to the auction listing if you want to treat the feline in your life to one-of-a-kind shelter or a bowl, but you'll have to be quick as it ends October 31.

A few highlights can be seen below, but head to the gallery to see each of the cat shelters.

Standard Architecture's shelter is named the Catosphere and comprises a concrete and wooden pod, raised on brass legs and fitted with a cat bed. The louvered wood walls can be open or closed depending on the weather.

The CAnT WE ALL GET ALONG shelter is designed by HKS. The slatted wooden structure doesn't seem all that practical for keeping out the elements, but on the plus side it does comprise a novel fish form and small birdhouses on its roof, meaning a fresh snack should never be too far away.

HOK is responsible for this unnamed seven-chambered shelter that offers protection from the elements for a group of cats. Its design allows entrance and exit from both the front and rear, while the interior is finished in soft felt.

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