Cellphone Piezo Speaker

[Zaphod B]

Oddball question here.

I recently upgraded my cell phone, and since my old one had a dead display I decided to indulge my inner 8-year-old and take the thing apart. I used the standard 8-year-old-boy disassembly tools - two flat-bladed screwdrivers and a hammer.

Marvels of miniaturization, these cell phones. Anyhow, before throwing the whole mess in the trash I popped out the little speaker. I'm assuming it's a piezo. It's a small flat cylinder about 1/2" in diameter and 3/16" deep with holes in both sides and a boss on the side with two terminals. I want to get some sound out of it but I can't think of an appropriate signal source.

Any ideas?