It started out as an exercise about CSS 3D transforms, but I got excited and expanded it a bit, so it became a minigame where you answer questions from the amazing Open Trivia DB. I used only pure JavaScript and A LOT of CSS. Since 3D support in CSS is limited, it features a hybrid combination of 3D and 2D graphics, with some shenanigans to make 2D look 3D. If you're interested, take a look at the source code.