[Fizzlemizz]

And if you don't want to remember what number is what power you can instead use:

Enum.PowerType.Mana
Enum.PowerType.Rage
Enum.PowerType.Focus
Enum.PowerType.Energy
Enum.PowerType.ComboPoints
Enum.PowerType.Runes
Enum.PowerType.RunicPower
Enum.PowerType.SoulShards
Enum.PowerType.LunarPower
Enum.PowerType.HolyPower
Enum.PowerType.Maelstrom
Enum.PowerType.Chi
Enum.PowerType.Insanity
Enum.PowerType.ArcaneCharges
Enum.PowerType.Fury
Enum.PowerType.Pain

Insanity = UnitPower("player", Enum.PowerType.Insanity)