Perferably not Classical music. Just a type of song when your just sitting around with your acoustic kinda messing around then start playing something.
Any style/genre in particular?
Tight Trite Night is a nicee one. Here is Andy Mckee playing a cover of it: http://www.youtube.com/watch?v=tn1d5DmdMqY
Muse's screenager intro is great to play on acoustic.