Magnetagram

magnetagram /ˈmæg-nɛtəˌgram/
noun.

A sign that takes on an entirely new meaning when a magnetic letter falls off

I am a brass-bound, copper-riveted, twenty-year old with some experience with the obscure, but I cannot, at this moment, recall an example. Do make up one for yourself.

Menapplause

menapplause \ˈme-nə-ˈplȯz\
noun.
a sexual joke or innuendo that gets big laughs from guys and scorns from girls.