Portals
The server has a custom portals plugin that allows players to create pairs of portals that then allow free travel to the opposite end. They are used with the /portal command, simply stand in the middle of a portal, type /portal, and you will be teleported to the other end of it, wherever that is. Each portal is paired with exactly one other portal, but players are able to create as many portals as they want.
Creation
To create a set of portals, first create the obsidian foundation as shown in the picture. This can face either direction. Then in the inside of the portal, place 1 diamond block and 1 lapis lazuli block. If the blocks do not disappear, and you do not receive any messages, then the location you are trying to use is already in use by another portal, or the blocks have not been placed properly. Make sure the portal is complete obsidian as shown in the image, including the corners.
Once you've successfully set one end of the portal, you should then travel to where you want the other end to be located. Be careful not to die during this period, if you die before finishing up the 2 portals, the one you've already placed will be lost. When you've reached the other location, simply repeat the process building an identical portal.
Additional information
The portals allow instant travel, but they can only be placed in the 3 vanilla worlds (the overworld, the nether, and the end.) It is possible to create portal pairs that go from one world to another.
To disable a portal, simply break one of the obsidian blocks. This will permanently destroy both ends of the portal, requiring you to build a new portal at both ends.