I learned a new word today, and it's paraprosdokian. I came a cross this word while i was reading a blog about grammar. I tried checking its meaning in a dictionary, guess it wasn't there yet, but it's in http://en.wikipedia.org/wiki/Paraprosdokian.
A paraprosdokian (/pærəprɒsˈdoʊkiən/) is a figure of speech
in which the latter part of a sentence or phrase is surprising or
unexpected in a way that causes the reader or listener to reframe or
reinterpret the first part. It is frequently used for humorous or
dramatic effect, sometimes producing an anticlimax. For this reason, it is extremely popular among comedians and satirists.
Examples: