Wipe down your countertops, cupboards and any other places where you've spotted ants with a 50-50 mixture of white vinegar and water. Repeat throughout the day to maintain the efficacy.
Why This Works: Two reasons, really: ants hate the smell of vinegar, and it removes the scent trails that they use to get around
Chalk/ Baby Powder
Draw a line of chalk or sprinkle baby powder across the spot where the ants are entering your home.
Why This Works: Talcum powder, an ingredient in both chalk and baby powder, is a natural ant repellent. Just be careful if you decide to use it: some studies have linked talc to cancer.
Mix together equal parts Borax and either syrup or jelly. Then, place where the ants will find it.
Why This Works: Once consumed, Borax damages both the ants' digestive systems and their outer skeletons, resulting in death.
Spinkle cinnamon, mint, chili pepper, black pepper, cayenne pepper, cloves or garlic whichever one you happen to have in the area where you've seen ants and along your home's foundation. Bay leaves can also be placed in cabinets, drawers and containers to further deter those pesky critters.
Why This Works: Many plants including the ones listed give off a strong scent to repel ants and other insects in the wild, and it works just as well in your home.
Sprinkle your used coffee grounds in the garden and around the outside of your house.
Why This Works: Ants are repelled by the scent given off by the grounds; and incidentally, so are cats.
Leave the peelings in areas of known ant activity.
Why This Works: Cucumber and citrus peels are toxic to the types of fungi that ants feed on, and therefore avoided by the ants.