I guess this could be good or bad, depending on how you define recreation: Drinking Seven Cups of Coffee a Day May Lead to Hallucinations.
Do not look at wine coffee when it is red freshly ground and brewed, when it sparkles in the cup and goes down smoothly. In the end it bites like a serpent and stings like an adder. Your eyes will see strange things, and your heart utter perverse things. You will be like one who lies down in the midst of the sea, like one who lies on the top of a mast. “They struck me,” you will say, “but I was not hurt; they beat me, but I did not feel it. When shall I awake? I must have another drink.”
(Proverbs 23:31-35)
Some people may find this hard to believe, but I seldom have more than five. 
I drank less before I bought the best coffee pot in the world. It grinds the beans, filters the water, and brews the coffee – all on a timer so I wake up to the smell of fresh ground coffee brewing. Should The Anchoress lay off the Mystic Monk brew? (CAN she?)
Old news to those of us who have blended sleep deprivation and studying with way too much caffeine!
I never hallucinated doing it, though.
Or were the things we all thought hysterically funny in those all-night study sessions chemically enhanced? Hmmm….!