You don't say how much musical knowledge you have away from piano. I play guitar, I've never studied piano and I don't own a keyboard instrument. But I can play bluesy stuff on the piano no problem. Here's a bluffer's guide to playing blues in the key of Am/C which is of course the easiest key to play on piano.
Right hand: Blues scale A C D Eb E G.
the Eb gives it the bluesy feel, especially if you play A C D Eb!
. You might get away with throwing in a B, but an F will sound way too jolly.
Left hand: play an A5
(E+A, with the E low.) Following the blues progression, introduce D5
(A+D) and E5
(B+E). To give more variation, build up rhythms by adding 6ths and 7ths (the notes in between the ones you are already playing.
The opening of Beethoven's Fur Elise follows a blues scale an makes an awesome crossover piece if you change the rhythm slightly.
Note: by A5
I mean A with no third. This term is common in rock, not sure if it is used in classical.