Like others I have both a shell history and a one-liners file, so anything particularly clever gets remembered somewhere :) Constructing on the fly though is half the fun of one-liners for me, and the repetition has improved my familiarity/knowledge of the language. It feels good when I have solved a problem (one-liner or scripted) without having to reach for a man page, text or WWW search.
How long before someone posts a suggestion for a new section called "one-liners"? <grin>
Life is a tale told by an idiot -- full of sound and fury, signifying nothing. William Shakespeare, Macbeth