Drums.

 This boy is obsessed with drums. In church. On TV. On Cd's. You name it. If it has a beat, he has a stick to accompany the beat (or spoon or toy...).
At this point i think he may be more of a rock band artist.  Head banging and all.
He started out with banging on every piece of furniture, so i gave him plastic containers. But he banged so hard he broke them.
SO, now we are back to banging on furniture (and big sisters).
OH-and never sit to close to him with a drum stick (we have learned the hard way!)
Of course we ALWAYS have to remind that drum sticks are for 'making music', not beating up sisters.
Oh the adventures with this one!