Bella, i feel your pain... i've had 2 separate summertime mega-battles with ants, one in the kitchen, one in the bathroom.
the kitchen --
they got into the breadbox one summer.
we didn't use it that often.
one day i open it up...
there were thousands of the lill bastids -- on everything; in everything!
we threw out that breadbox with all its residents...
the bathroom --
unbeknownst to either of us the shower wall (which has a window) was made of cheap plasterboard, and it got 1 or 2 soakings per day for years.
one day we strted noticing an ant or 2 on the window sill.
no big deal -- they prolly crawled thru the screen... NOT!
a few days later (the 4th of july no less) i saw one crawl OUT OF a tiny crack in the paint.
damnit, i thought to myself, i gotta do it.
so i ripped open the wall... sure enough, another colony of the @#$%&'s.
i must've spent 3 or 4 hours killing ants.
i was determined to wipe them out single-handedly!!
soon thereafter, we had the shower renovated (which we'd been meaning to do eventually anyway...)