Many people had learnt this game from Jeremy Zawodny's blog. Similar to the Jeremy, I hardly play video games anymore (although I have XBox, PS2, PSP, NDS). Not I don't like play video games, but I just really don't have any time to play video games at all. I am just a causal gamer but not a hardcore gamer.
Desktop Tower Defense (DTD) proves a simple and causal game can be highly addicted and very popular. I ran into multiple blogs and people are "complaining" that they are addicted into the game and they cannot get anythings done!!!
Besides the game playing, I like the author of this game keeps updating the game. He constantly adding new rules and weapons into the game and make it very interesting.
Readers. You should try this game if you haven't. Trust me, you will be addicted immediately.