Corrected entry: In the first couple of minutes of the film, the Dan Ackroyd character (Harry Sultenfuss) sings the lyrics to the Madness tune, "Our House" ("Our house, in the middle of our street", etc). The movie is set in 1974, but Madness didn't release that song until 1982.
Corrected entry: In one scene, a boy in the classroom admits to having the hots for Farrah Fawcett. The problem is this film takes place in 1974 and Charlie's Angels didn't premiere till 1977, so how could this boy even know who she was? At that time she'd only done small, unmemorable parts. Farrah was not a big sex symbol until Charlie's Angels.
Correction: Accordiong to imdb.com, Farrah started acting in 1969 and appeared in several popular TV shows in the early 1970s; I Dream Of Jeannie and The Partridge Family among others. The boy could easily have seen her in those shows and others.
Correction: Harry is not singing 'Our House' by Madness. He is singing a much older song, with the same title. It was performed by Crosby, Stills, Nash, and Young. It was recorded on the album entitled "Deja Vu", in 1970 and written by Graham Nash (check out the song credits at the end of the film). What he is singing doesn't even sound anything like 'Our House' by Madness.