I read somewhere recently that ants outnumber us people
by weight!
The article also called ants 'the garbage disposal system of the universe'.
Have you tried communicating with them? They have a kind of group consciousness, so don't try communicating with them individually. Usually this method works for me, but I gotta say that ants are more persistant than most pests.
I had a pretty bad infestation last summer, when they found the way to my kitchen counter. I politely asked them to leave, and gathered them all up and deposited them outside. Ants use scent trails, so a deodorizing cleaner helps. I've heard that you can just draw a line of chalk, and the ants won't cross it, but I've personally had more luck with baking soda.
But the ants didn't actually leave. There were less of them, but they kept coming back. Finally I got so frustrated that I visualized connecting to the ant Deva the best I could and I said "Look I tried to do this the easy way, but you're not cooperating. From now on I will kill all the ants that I find on this kitchen counter."
Then I cleaned everything up again and tried getting rid of their scent trails the best I could, and I haven't seen any ants since then.