i counted no less than 35 references (pretty good for a half hour show). some were so obscure that i'm not even sure if they were intentional,or or rather just coincidental. at the same time, i'm reasonably sure i probably missed some.i have the episode on tape, just so i can enjoy the episode again and again, as well as look for other "oz" references.
it only took a few minutes to catch on to the gist of the episode , as it used hints here and there . however, even if someone was somewhat "oblivious" to what they were doing, by the middle of the episode, only someone who had no clue about the wizard of oz wouldn't catch on.