Bukkit

/tp <player>
Very simply, it will let you teleport to a player. Nice and simple.

/tphere <player>
Lets you teleport another player to you!

/scare <player>
This will shoot a lightning bolt down at that player (harmless)

/time <day/night>
This will let you change the time of day it is in your current world.

/lightningaxe
This shoots a lightning bolt down at where you are pointing! Harmless!

/creative
This will turn your server completely creative. Unlimited blocks + instabreaking.

/weather <sun/rain>
This will let you change the type of weather your world is currently having.

/rocket <player>
I had alot of fun of this, it will shoot the player into the sky!

Anyway need any more help, check out the forum!