If Marty McFly went back in time thirty years ago today, what song does he play at the dance to blow everyone's mind?

"Then tell me futureboy - who's the President of the United States in 2017?"

well, looking at the biggest hits from 1987 et 1988, I don't see anything that he could play to them shortly before it hits that would be a shock...
but "Pump up the volume" seems a good answer. Or maybe some new jack swing ?

or "Straight outta compton" released in 88.

Voodoo Ray? A bit late maybe, having been released in 89.

Though recorded June 88.

actually, in the movie, he plays jonnhy b good 3 years before it's released.
so we're looking for something from 1990 !

snap : the powa !

Killer - Adamski

91, but whatevs.

I'm not sure some of these would be especially out-there to people who were used to some of the more epic synthpop of the mid-80s. Like at this stage he'd be playing some house music and people would be into it but they really wouldn't be expecting a veer into, say, 'Original Nuttah' by Shy FX. Or any jungle really.

Actually that's probably the metal guitar solo bit rather than the Chuck Berry bit.

oh I've got one : "Smells like teen spirit" ! "91, the year punk broke" !
for mainstream kids from 87, that would be a big wtf, I guess.
and exactly like in the movie, I could see the actor smashing everything at the end of the performance in front of the audience in awe and struck by feedback.
on the other hand, that wouldn't sound much like the future in a "this will change everything" way...