Futurological Congress, The by Stanislaw Lem

I have to say that this is one tripped-out affair. One hell of an original storyline with endless twist and turns coupled with nonstop action. Its a really quick read as well, and although the length keeps it from being any sort of epic it still rates up there as one of my favorite sci fi books of all time. The amazing descriptions of mind-altering drugs and their social effects on humanity paints an awesome picture of a dystopic fantasyworld. This one keeps you guessing till the end- you won't want to put it down.