The launch track is a less serious track and more for fun.
As the name says it, launches you into the air. It's very expensive though, requiring 2 Steel blocks, 4 Reinforced Rails, a Piston, and two Stone Railbeds, and only giving you two tracks.
There are some interesting ways you could use this rail, such as:
Bombing. You could activate a TNT Cart then launch it at someone's base.
Roller coaster. If you're making a roller coaster or a train system going around your map or server this could keep it interesting.
Be creative! Come up with your own ideas!