Well, this little gem is very simple, not really a lot of fun, but still horrbily addictive.

Prepare for Ant War!

You control the destiny of a colony of ants. Each day you choose their activity, and attempt to create the largest colony that you can.

Warning though, you do have the option to save your game, but you must first sign up with the site, then Pay $0.50 per save using PayPal. I am not sure how much it would cost to load a game (if anything).