released in 1977
by the Children's Television Workshop
that was a parody
of Saturday Night Fever
The cover features Grover in full John Travolta disco regalia on the lighted disco floor, and Bert, Ernie, and Cookie Monster in the Bee Gees cameo shots on the top of the cover.
The music is, basically, evil. In fact, Robin Gibb actually wrote some of the songs, but the others were remakes of other Sesame Street songs. This album really bothered me at the time. I've mellowed since then, but seeing Grover tarted up that way is still not right.
There's a site with way too much info about this and the sequel Sesame Disco at http://sesameseventies.com/sesamestreetfever.html