In the 2nd Season of Futurama there is an episode, "The Problem with Popplers". Fry and Bender find a planet full of tasty things (the "popplers") and sell them to Fishy Joe's (a fast food place). They then record the theme song for the popplers, which is this:
Pop a Poppler in your mouth
When you come to Fishy Joe's.
What they're made of is a mystery
Where they come from no one knows,
You can pick 'em, you can lick 'em, you can chew 'em, you can stick 'em.
If you promise not to sue us you can shove one up your nose.
Some researchers (you know, nerds) have found that played backwards, this song gives a devious message, that reaches our subconscient while watching the episode:
Explore Neepa-Noopa's snippers
Sue us if that snarb ekay mikkets
If we moosh, miffy licka, lick me murka
If we saw another Noofa in a wheelchair,
Mr. Rayanetto sauce!
He shaved the monkey love farm in your roof.
If you don't believe us, listen for yourself: