Gack
A Gack is any item (other than a bottle opener) which is used to open a beer bottle.  This applies only to bottles filled with beer.  Soda, juice, de-alcoholized beer etc. do not apply.  It must also not be a screw-off bottle.  Due to the skill involved, a person who is rather adept at using various items to open a beer is referred to as a Gacksmith.   
My buddy Todd is a real Gacksmith.  He can make a Gack out of anything!