Antigrams&Trianagrams.

Antigram - an anagram that means the opposite of the original word or phrase; 
    Example : restful is the antigram of fluster 


  Here are some more examples:
    * Santa ‡ Satan.
    * United ‡ untied.
    * Funeral ‡ real fun!
    * Forty five ‡ over fifty.
    * Militarism ‡ I limit arms.
    * Saintliness ‡ entails sins.
    * Antagonist ‡ not against.
    * Evangelists ‡ evil's agents.
    * Protectionism ‡ nice to imports.
    * Within earshot ‡ I won't hear this.
    * Sweltering heat ‡ the winter gales.
    * The Oscar Nominations ‡ It's not a cinema honor. 




Trianagrams : words that create three perfect anagrams :


Examples:
* Fare: Fear: Frae
*Feat: Fate: Feta
*Flow: Wolf: Fowl
*Listen: Silent: Tinsel
*Miracle: Claimer: Reclaim
*Parental: Paternal: Prenatal


......more here.