From 1972 to 1992, Rainbow, a children's telelvision series, aired twice weekly in the U.K.  The show was intended for pre-school children to develop language and number skills. 

After watching this show our kids will be ready for a cold shower and a cigarette.

Note: "In 1979, the cast and crew of Rainbow made a special edition for the Thames TV staff Christmas tape. This show featured plenty of intended sexual innuendo, and although not shown at the time (as it was never intended to air), it has since been aired for the amusement of those who grew up with the show." [Wikipedia]

[via digg]