A Zipper elevator is a redstone mechanism with pistons to transport players upwards very quickly. I made a really nice one with ejection system, water security and doors. In single player it works perfectly. On a server you might fall through the pistons if its laggy. On my server it works 80% of the time, and if it doesnt, you wont die because you fall into water. On laggy servers u can try a few times untill it works.
You can make it bigger with worldedit, but the longer the elevator, the more probable it is to fail. In the video i made several elevators after another to reach higher heights.
The doors have a purpose too, without them you tend to get pushed out of the elevator when it starts.