Every now and then a song comes along that is so catchy and has such great hooks, that it just sucks you in after the first listen and doesn't let go.
Currently, for me, that song is Fireflies by Owl City. (As of this writing the song plays as soon as you get to the web page.)
This is electronic music that has also been described as "computerized pop". There's no band, just Adam Young sitting in front of his computer. Don't write it off until you hear it - my 11 year old was hooked after one listen as well. In fact, I dare you not to like it.
Fireflies had the potential to be the monster hit of the Summer - it's THAT irresistible. Unfortunately, as I type this, it's the last weekend of the Summer. Nevertheless, I suggest cranking it up loud -- in your car, on iPod, at home and ride the wave for nearly four minutes.
Owl City's Fireflies - Music You Need to Hear