Tons of old school horror films. Anyone ever see Todd Browing's Freaks? But while trippin' balls, though? Let's jut say it's quite the memorible experieance. Try to take some acid an hour and 20 minutes before, and then get ready for a unique ride.
Especially
Texas Chainsaw Massacre (1986) while tripping during the opening bridge killing of the preppy yuppies attack set to Oingo Boingo's No One Lives Forever, and also all of the old school Paramount era
Friday the 13th installments. Part 3 (in 3-D no less) and the pseudo-Jason (basically Jason-less)
Part V (1985's A New Beginning) especially.
Happy smoking & drinking.