There use to be a bar in Lexington in the Chevy Chase area called Stingles. Not sure what is there now, but it was across from Charlie Brown's.
Stingles had a Happy Hour each Friday afternoon with three-fers for the price of $0.80. Yep - eighty cents for three hard liquor drinks.
Since this was back in the - ahem - disco era, Stingles' dance floor would become quite popular as happy hour progressed.

Needless to say, after a few Singapore Slings you were ready to Get Down and Boogie.