Fruit flies can be an annoyance but you can get rid of them using stuff right from your kitchen, no tools required. One method is to pour apple cider vinegar in the bottom of a glass along with some dish soap. Come back after leaving it out for a few hours and you’ll have yourself a nice cup of dead fruit flies.
The flies are attracted to the sweet odor of the vinegar and the dish soap breaks the surface tension of the water so they fall to the bottom and can’t escape. The dish soap apparently also messes with their cell membranes.
No cider vinegar around? A banana peel works just as well. Honey, too.
Capture Fruit Flies with a Cup and Apple Cider Vinegar [Lifehacker via Cool Tools]
Fruit Fly Death Trap [Re-Nest]