If I remember right, a mason jar with sugar water an inch deep or so with a small hole in the cap for them to enter. The flys are not smart enough to fly upwards toward the hole to excape.
I’m handy with a flyswatter, too, and it’s as good as a tennis workout, but today I just don’t have the necessary reserve of rage and hate to start swatting. I put a cup of vinegar, orange juice and dish soap and filled with water to bubble it up - someone on yahoo help recommended this - and they’re entirely avoiding it.
Bug zapper sound like a good idea - flies really like them? I was thinking about using the shop-vac on them, too.
They just show up out of nowhere this time of year. No horse stables, turkey farms, anything that might explain their sudden everywhereness.