Redditor Ergas has a disgusting way to lure fruit flies to a very personal fiery death.
LPT: If you have a ton of fruit flies in your house, turn off all but one light source and wait 2 minutes. They will congregate there. Then, flick on a lighter and turn off the light source. The flies will burn their wings off trying to get close to the light source.
(Image: Fruit Fly Died, Kevin Bowman, CC-BY)