I posted this tip last year and thought I'd share it again since recently I needed it myself.
To get rid of those little fruit flies that like to hang around your kitche and fresh produce and like to drive you crazy, here's what you do. Take a small glass or dish and pour cider vinegar in it to about half an inch depth, then add one to two drops of liquid dish soap. They are drawn to it by the vinegar but drown in it due to the soap changing the surface tension.
This really works great. Try it for yourself.