Post your favorite derp build.

[Ghostfang]

a derp build is a build that wouldn't normally work but you found a way to make it work for casual play... no hardcore raiding builds ... just builds that don't make sense but somehow work

mine is leveling frost dk as a tank in dungeons, full tanking boa duel wield parry swords spamming howling blast while keeping conversion up.

http://www.wowhead.com/talent#kx^N|osm

[MstrPlnr]

Demonology warlock with Glyph of Demon Hunting. You turn into a tank. You also take the glyphs and talent choices I outlined and then Grimoire of Sacrifice your voidwalker and there is an additional 30% health buff for 12 seconds. My ilvl 530 warlock is @ a smooth 800k hp, and breaks 1 million when I use that 30% health boost. I don't suggest raiding, but I have been able to tank Heroic Scenarios with ease, no healer required.
Mists of Pandaria - Talent Calculator - World of Warcraft

[Garalon]

I don't really know about DK's but i know more about hunters and you can find a really nice guides about your Class talent build, glyphs, damage/tanking rotation, reforge gems and enchant.
Class Guides (WoW MoP 5.4) - Icy Veins