A compilation of songs (traditionally on a cassette tape, though CDs are acceptable) that one makes for oneself or another, normally a boy or girl they like. Fine examples of mixed tapes have liner notes and a snappy title. Some fools say: mix tape or mixtape but this is clearly wrong as you have mixed a tape for your or another's enjoyment.
"Here Nate, I made you this mixed tape over Christmas break."
"Oh you mean you made me a mix tape?"
"Never mind, I don't like you anymore."