Demos incríveis feitos somente com CSS

Nada de JavaScript!

https://codepen.io/Mamboleoo/pen/oxaXdj

https://codepen.io/alexandrshy/pen/ONGoPW

https://codepen.io/Adir-SL/pen/LYEPzxW

https://codepen.io/amit_sheen/pen/XJbqgOr

https://codepen.io/neoberg/details/DEZbKv

https://codepen.io/tippyfodder/pen/OyXWpr

Alguns são inclusive interativos!

https://codepen.io/jsulpis/pen/VwBNoEb

https://codepen.io/jh3y/pen/ExNQxKV

https://codepen.io/smpnjn/pen/mdxzLWo

E aqui uma espécie de Windows 98 funcional!

https://codepen.io/smpnjn/pen/ExLbvdJ

Vocês conhecem mais exemplos?