Ellen's parents find her sulking atop the "Hollywood" sign, however in real life that area is blocked off so that nobody can climb the letters.
(Ellen is sitting in the "o" of the Hollywood sign playing the harmonica)
Police Officer: Hey you, get out of the "o". And you in the "w" - put your pants back on!
Ellen mentions that she may as well be hiding a dark secret for all of her life, such as being left-handed. In the light that Ellen comes out as gay later in the series, this is very likely an allusion to that possibility.
In the beginning of the episode, Ellen is coming out of the closet (literally).
Opening sequence: Captain & Tennille.
Paige sings a dedication for Harold's retirement on camera that is based on the famous song by Marilyn Monroe, "Happy Birthday Mr. President".