Cross rhythms such as 5 against 4 or 7 against 8 are common.
Putting objects in the piano to create new sounds on the strings or using the piano for knocking or tapping as part of the music.
John Cage Dice Random notes
Using one key for the right hand, another key for the left hand.
Cloudbursts by Eric Whitacre
Non-traditional scales
Irregular time signatures
Prepared piano
5/4 or 7/8
Chance Music
Blues scales or modes
Bitonality
Polyrhythms
Cluster chords
