A Cold Cup of Jones is a cold beverage in a coffee cup. It's milk with a few scoops of coffee ice cream blend together, topped with whip cream with blue sprinkles on top.
It's a hot day today. Whenever I feel hot, tired and thirsty, I make myself a nice Cold Cup of Jones.
"My toes hurt!!! Aww... my back just ain't what it used to be. Did you see that, Gladys? Did you see that?"
"Hey, Janie, how about a nice, cold cup of SHUT THE FUCK UP?!"
When, usualy a joke or another comment (but could also apply to a film or play etc), is either not appreciated, said when not appropriate or just plain not funny and get's either a cold response or no response at all. Similar to a lead balloon. It can be described as "Going down like a cup of cold sick".
When George told his joke, about The Englishman, the Irishman and the Scotsman, in which the Irishman appears stupid, at an Irish social club, it went down like a cup of cold sick.