Grapple is the second plugin in my line of mechanic adding plugins! Press Q while holding a tripwire hook to throw a grappling hook, and be pulled in when it makes contact! No commands, one permission, a good simple grappling hook that I couldn't seem to find elsewhere.
Depending on how your server is configured, players may be stopped midair for speed hacking. To solve this, upgrade to the newest Craftbukkit, which seems to be more lenient in accusing players of hacking. If you use NoCheatPlus or another anti-cheat plugin, additional configuration to that plugin may be required in order to allow players to travel at higher speeds.
grapple.use - allows use of the grappling hook, otherwise pressing Q with the hook will simply drop it.
This plugins will be maintained until it becomes impossible to do so, which probably wont happen! Content updates will be based on bugs reported in the comments, and the results of the update poll.