They've got a term for it?!

earworm: Information From Answers.com

Earworm, a literal translation of the German Ohrwurm, is a term for a song stuck in one's head, particularly an annoying one.

Use of the English translation was introduced by James Kellaris, an associate professor of marketing at the University of Cincinnati. His studies appeared to demonstrate that different people have varying susceptibilities to earworms, but that almost everybody has been afflicted at some time or another.

Here are some recent examples of earworms:

* The Lion Sleeps Tonight — Solomon Linda
* We Will Rock You — Queen
* Take A Chance On Me — ABBA
* Who Let The Dogs Out — Baha Men
* Whoomp! (There It Is) — Tag Team or the similarly named Whoot (There It Is) by DC Tag Team
* YMCA — The Village People
* Macarena — Los Del Rio
* Feliz Navidad — Jose Feliciano
* Barbie Girl — Aqua
* Dragostea din tei — O-Zone

as well as several songs for children:

* "it's a small world" — Sherman Brothers
* This is the Song That Never Ends — Shari Lewis & Lamb Chop

and various advertising jingles for food items.

Wowie! I love the 'this is the song that never ends' song :) and Kir's earworm was Jhandu balm, jhandu balm, tera har (whatever) .. So cool! :)