The Disco-movie of the year 1978 is "THANK GOD IT'S FRIDAY'.
It's a movie full of disco-music, disco-people and disco-stuff. At the disco "The Zoo" is on a Friday-night a dance contest and the Commodores is the great live-act of the evening.
D.J. Bobby Speed is spinning the records that evening and he's trying to get his friend Floyd at the disco in time with the instruments for the Commodores.
Nicole (played by DONNA SUMMER) is a singer trying to break through. In the film she tries to get to the D.J. in order to sing her song on stage that night. At last she get's her chance and sings "Last dance" (this song won the Oscar for best song in a film that year)
Marv "the Leatherman" get's his chance to show his stuff also and he tries to learn everybody his steps.
Computers were in those days also involved with dating. Gus and Shirley were put together by computer, but what the computer didn't know was that Gus was a little shorter than Shirley which made some unusual scenes.
Jackie is a girl who experiments with pills to get energy to dance.
Two girls who are too young to get into the Zoo try everything to join the dance contest. One of the girls was played by Terri Nunn, leadsinger of the group Berlin ("Take my breath away")
Then there's the couple Dave and Sue. They
stand accross the street watching the crowd in front of the Zoo.
Sue gets curious and wants to go to the Zoo, but don't seem to
get Dave with her. At last he goes with her and gets into the
arms of Jackie and Sue into the arms of the Zoo's manager (played
by Jeff Goldblum). 
Other than "Saturday night fever" the movie "Thank God it's Friday" offered the DJ's a great 10-issues 12" single promo-package of the soundtrack.
The 10 12"singles are:
-After dark (7.55)-PATTIE BROOKS NBD 20116DJ
-With your love (7.35)-DONNA SUMMER NBD 20117DJ
-Take it to the Zoo (8.23)-SUNSHINE NBD 20119DJ
-I wanna dance (7.31)-MARATHON NBD 20120DJ
-You're the most precious thing in my life (8.10)-LOVE & KISSES NBD 20121DJ
-Last dance (8.10)-DONNA SUMMER NBD 20122DJ
-Thank God it's Friday (7.40)-LOVE & KISSES NBD 20123DJ
-Do you want the real thing (12.15)-D.C. LaRUE NBD 20124DJ
-Disco queen (8.10)-PAUL JABARA NBD 20129DJ
-Find my way (5.18)-CAMEO CCD20014DJ
Now the soundtrack is released as double-cd by Polygram Records.
The video of the film is released by Columbia/Tristar Home Video