Hit the Deck (Fallout: New Vegas)

Hit the Deck is a Fallout Tactics, a J.E. Sawyer's Fallout Role-Playing Game and Fallout:New Vegas perk.

Fallout Tactics
You react very quickly to the word "incoming!". Halves the damage from area attacks and splash damage.

Fallout: New Vegas
Your extensive familiarity with Explosives allows you to ignore a portion of their damage. Your Damage Threshold is increased by 25 against any and all Explosives -- even your own. This makes Hit the Deck one of the best perks in the game for a character who makes heavy use of Explosives.

Bugs
Prior to patch 1.4.0.525, this perk was bugged. Rather than increase your DT versus explosives, it would instead increase your DT if you had an explosives skill type weapon equipped. New engine functionality in the patch allowed for this perk to be corrected, and it now functions as intended.

J.E. Sawyer's Fallout Role-Playing Game
You react very quickly to the word "incoming". When hit by damage from explosions or sprays, you are considered to be an additional 2 hexes away from the origin for purposes of determining damage.