For my music class at school I have to play a piece, any piece that goes from 3-5 minutes. I wanted to do a song by myself on the acoustic but I don't know what to play. I can't sing so I would have to be playing the melody and chord progression. I'm not too high in skill level.
Try Greensleeves. It's fun and not too difficult.
Or Lagrima is a playable classical guitar piece. You should be able to find tab on the net.
Ocean - John Butler Trio