Modern-day psychedelic rockers MGMT went way back in the Pink Floyd songbook on tonight's episode of 'Late Night with Jimmy Fallon,' performing 'Lucifer Sam' from Floyd's 1967 debut 'The Piper at the Gates of Dawn.'

It was all part of Fallon's week-long Pink Floyd tribute, which kicked off with the Shins tackling 'Breathe' following an interview with drummer Nick Mason on Monday. Bassist Roger Waters teamed up with Foo Fighters to perform 'In the Flesh?' on Tuesday, in addition to sitting down for his own chat with late night's giggliest host.

The Floyd love continued right from the start of tonight's show, with big-shot movie star Anna Farris revealing 'Wish You Were Here' was the soundtrack she used for stalking an ex-boyfriend years ago, and 'Lost' star Michael Emerson explaining that he's been listening to 1970's 'Atom Heart Mother' a lot lately.

Fallon was notably excited to see MGMT in action, frequently assuring the equally rabid audience that the band would be coming out soon enough. At the end of the show, they finally did arrive, awash in bubbles and dry ice, dressed up in fisherman's outfits, to perform a very faithful version of the swirling, spooky track.

They did a fantastic job, and it was by far the most "out there" performance of the week so far, honoring Pink Floyd's earliest and most experimental music. We wouldn't bet on country star Dierks Bentley or Pearl Jam heading that far into the cosmos in the coming nights, but it should still be something to see.

Watch MGMT Perform Pink Floyd's 'Lucifer Sam' on 'Late Night with Jimmy Fallon'