Izzy, you are so funny!!!
My dad ALWAYS had problems with them because he always had bananas. Ugh. Sometimes there were just gross swarms of them.
Here is a really, really, REALLY effective way to get rid of them: take either a narrow-necked bottle (like a Coke bottle) or another jar (in which case you would make a scroll/cornucopia out of a piece of paper, and tape it so the narrow end is well into the jar). Put an inch or so of apple cider vinegar (has to be AC; white or wine, etc. won't work) in the bottom.
Fruit flies will go into it like magic. They go down the paper, into the cider, then either drown or can't find their way out again (and drown).
It's not the most appetizing-looking thing, but it sure gets rid of them!! You can put a drop or two of dish detergent in it, too. It acts as a surfactant and "glues" them to the cider. But it's not necessary.
