Shave and a Haircut - Banjo Tab and Sheet Music
This short riff is often used at the end of a piece of music. Because the riff is centered around two notes (tonic and dominant) it can easily be used in any key if you understand some basic music theory. If you figure out the tonic and dominant for a key, you can just look at the other notes in the riff in relation to them. For example, the last two notes of the riff are a half step below the tonic and the tonic itself.