The act of beating someone to death with hammers.
From the 30 July 2003 Onion article "Gigli Focus Groups Demand New Ending In Which Both Affleck And Lopez Die"

"According to the exit cards, other popular methods of achieving Lopez and Affleck's on-screen demise included car bombs, multiple stab wounds, acid baths, rabid wolf attacks, lightning strikes, and, in one case, a "hammer party."
by Americus Symmes June 24, 2004
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Some gay guys who use there dicks as "Hammers" they bang in the nails with their Penis's in order to make it into a four-by-four. If nail is fully in and their penis is not throbbing with pain. Then they get oral sex by some really hot hot hot muscle toned buff guy.
" Carl is the winner" said Jake
"Oh, good my dick needs some wet rubbing after all of that nail banging"
by James Wood June 26, 2004
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An event you invite someone you truly hate to. During which you get said (male) drunk, or via force, tie them to a chair, and use a hammer to smash their nuts to a bloody pulp.
me - Yo, you see that guy over there?
you - yeah I see him.
me - he raped my sister, lets invite him to a hammer party
by the_carrot September 11, 2007
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