A Tom swifty is a one-line play on words involving a punning relationship between the way an adverb describes the action of a speaker and the content of the speaker's statement.   Tom Swift was the brainchild of Edward L. Stratemeyer (1862-1930).   Under the pseudonym Victor Appleton, he published a series of books featuring the young Tom Swift.
Tom Swift rarely passed a remark without a qualifying adverb.

Examples of Tom Swifites

Tom Swifties #1

Tom Swifties #2

Tom Swifties #3

Tom Swifties #4

Tom Swifties #5

Mathematical Tom Swifites (11/8/2004 Problem of the Week)

Mathematical Tom Swifites (sent in by Problem Solvers)