Most annoying ringtone you've ever heard

[Ron Mexico]

I was recently behind someone at a newsstand who had a "Hollaback Girl" ringtone. My first instinct was "if I kill her now, with a clean record and former military service I'll probably get out in five years." ;)

She still lives, but she must be stopped. If there is justice, a bus will flatten her soon.

Who has irritated you the same way with a ringtone and what was the tone?