Move.
Just kidding. But in our old house, about 3 weeks before we moved, there were suddenly MASSIVE amounts of ants - everywhere!! BIG black ones! they were coming out from behind the crown molding between the wall/ceiling. We'd find HUNDREDS every day and they were mostly in the kitchen, which was just *disgusting*. We used some ant traps that were a pretty good temporary fix - a couple cheap-ish ones from Home Depot. Raid is also a great short-time fix, until you can get in an exterminator or something.