After the family yells "surprise," as they walk up to greet Marion, a camera appears in the lower left-hand corner.
Notice the mysterious moving furniture/camera during the opening moments of this episode.
Fonzie: Mork, you came all the way down here from Ork?
Richie: Oh, no. He's, he's living on the Earth now. Only in the future: 1979.
Fonzie: In the future. Two things I gotta know: cars and girls.
Mork: In 1979, both are faster.
Mork: Greetings, Cunningham. I bring you greetings from the Cosmic Congress, the Stellar Confederation, and Mindy.
Richie: Is that a heavenly body?
Mork: Oh, she must have something because I'd be willing to walk 10 miles in the snow to stand in her garbage.
(Mork and Richie discuss 1979 - the year in which Mork lives.)
Mork: You remember Nixon?
Richie: Oh yeah, whatever...?
Mork: Don't ask.