Babylon 5: "All Alone In The Night"
"We have always been here. Your mind just wasn't quiet enough to hear us." Awesome.
Third Rock From The Sun: "Nightmare On Dick Street"
The High Commander and his squad have been human long enough that they start having dreams. Including this truly weird, amazing musical number.
Star Trek: First Contact
Captain Picard is having a wee bit of post-Borg traumatic stress... just in time to meet the Borg again.
The classic "melting playground" sequence.
Sil escapes on an Amtrak train, but dreams it's turning into an H.R. Giger monstrosity, with bones and weird mouths everywhere. Awesome!
Tom Cruise has a weird, trippy dream that he's in I Am Legend.
Buffy The Vampire Slayer, "Hush"
"If I kiss you, the sun will go down." Joss Whedon is so fancy.
Twin Peaks: Fire Walk With Me
David Lynch figured out that if you make twenty dream sequences, the twenty-first gets to feature David Bowie.
But we still love this non-Bowied sequence as well.
Another Terry Gilliam film, another trippy sequence — Bruce Willis dreams of the event that's simultaneously his past and his future, filtered through super-bleached light.