WCA (The World Cube Association) hosts cubing competitions worldwide for a specific group of puzzles which have been appropriately dubbed "WCA puzzles". There are about 10 WCA puzzles in existence, but several of them have subsets such as OH, blind, and... 3x3 with feet? Wat? Amongst all of this though there are many cubes that have been dropped from WCA after they were in the system for a while. Cubes like the rainbow cube, rubik's magic, and more (I think). With this, many people want more cubes to be included in comps. WCA does bring new cubes into competitions regularly, normally at the beginning of the year, but they don't always. Skewb is the most recent event added, which was added n 2014.
WCA competitions must follow WCA regulations. Regulations can change, and occasionally do. A good example of this was when stickerless cubes were banned from WCA competitions a while back, and in the summer of this year they were brought back. With this change in regulations came a regulation requiring devices to be put in place to prevent squans from moving during transport to the competitor.
WCA regulations also mandate a certain kind of timer. Competitions always use Speed Stacking timers. It is slightly confusing seeing as cubing companies do make timers, yet we don't use them. It makes sense when you realize that Speed stacking timers are much higher in quality, but regardless, it's still confusing.
Competitions are few and far between in many places. Here in California they happen regularly, but in many places cubing competitions don't happen at all. So if you cube and you hear of a competitions happening near you, make sure you go. You'll love it. Trust me. If you're a cuber, that is.
Venomburners! They eat your mana in the darkness, Jimmy!
-GIR