
Title: Put On A Happy Face
Used During: The scene at the nuclear power plant as Homer gets eaten.
From: Bye Bye Birdie
Album: Bye Bye Birdie Soundtrack
Lyrics

Title: Bei Mir Bist du Schon
Used During: Mulder and Spender's fight. Plays on the radio.
Recorded by: The Andrews Sisters
Album: All Time Favorites
Lyrics
Title: Jeepers Creepers
Used During: Ballroom scene.
Recorded by: Sally Stevens (Kersh's assistant - whatever her name was - "performed" it during the episode.)
Do I even have to bother with the lyrics?
Album: 1941 - Original Motion Picture Soundtrack
Used During: The swing music at the end
From the Season 6 Guidebook: Mark Snow "concedes that the episode's most memorable composition - the bouncy instrumental played during the split-screen chase scene - was kickstarted by John William's earlier retro swing tune composed for the fight scene in the movie 1941.
**A note about this music - it is not "Sing, Sing, Sing (With A Swing)." I'll break it down like this: Mark Snow borrowed from John Williams, John Williams borrowed from Benny Goodman. Similar styles, similar song, but not the same. Also - I've never seen 1941 and I'm not familiar with the score, so I'm still trying to figure out the exact title for this piece. If anyone knows, please drop me a line.

Title: Let's Get It On
Used During: Morris Fletcher (as Mulder) sings this before attempting to seduce Scully.
Originally Recorded By: Marvin Gaye
Album: Let's Get It on
Lyrics
Partial Lyrics
Used During: Scene at the Little A'Le Inn.
**Me again - if anyone knows the title of the song to go along with the above lyrics, let me know.

Title: Have Yourself A Merry Little Christmas
Used During: Entire episode.
Recorded by: Bing Crosby
Album: Bing Crosby's Christmas Classics
Lyrics
**Originally recorded by Judy Garland for the film Meet Me In St. Louis.
Different lyrics
Thanks, Megan!

Title: Only Happy When It Rains
Used During: Wayne's attempt to drive to his other home and the final scene as Betsy drives away with the demon baby.
Recorded by: Garbage
Album: Garbage
Lyrics

Title: Rainy Days And Mondays
Used During: Teaser - Daryl wrecks his car.
Recorded by: Sally Stevens
Originally recorded by: The Carpenters
Album: Best Of Carpenters
Lyrics
Title: Rock The Boat
Used During: Class Reunion scene.
Recorded by: Hues Corporation
Album: Rock The Boat
Lyrics
Title: Things We Do For Love
Used During: Class Reunion scene.
Recorded by: 10cc
Album: Deceptive Bends
Lyrics
Title: Over The Rainbow
Used During: Final scene - starts at the reunion and ends with Sheila and her baby.
Recorded by: Judy Garland
Album: The Wizard of Oz Soundtrack
Lyrics

Title: Come And Go With Me To That Land
Used During: One scene on the team bus and, of course, at the end with Mulder and Scully hitting a few.
**Pretty sure this was a special arrangement for the episode.
The best known version is by: Bernice Johnson Reagon
Album: River Of Life/Harmony One
Lyrics

Title: Dies Irae
Used During: Quoted by Mark Snow during the final scene as Scully sees the ship.
**Thanks, penny!
Lyrics
**Mark Snow's score didn't include these lyrics, but they might illustrate the effect he was going for a bit more. Thanks to the Madd Hatter and Daniel for these!