Invented in 1974 by Ernõ Rubik, the original classic Rubik's Cube is a puzzle where, each of the six faces are covered by nine stickers, each of one of six solid colours: white, red, blue, orange, green, and yellow. Over the years, the cube has seen many changes in colors, shapes, sizes, difficulty and even the pieces have changed! This of course resluted in various kinds of the puzzle, that sometimes look completly different to the original one! There's many ways to enjoy this puzzle, but my personal favourites are modding, collecting and speedcubing!
Modding, is the act of modifying your average cube to make a new, never-seen before version of the original! Think it like this: A mod of the cube is a change in it's shape, colors, etc. The mirror cube, the Ghost and the Windmill are all shape mods. Sticker/Color mods are those cubes with color schemes different to the usual 6-colors or with entirely new patterns, for this, an example is the Calendar cube! So, modding is the act of making these changes yourself!
Speedcubing is, well, solving a certain cube as fast as you possibly can and searching ways to become faster and faster, like getting the best cubes or practicing a lot! I swear it's fun!
Check out the WCA to learn more on this one!