Help Help, I'm being attacked

Chris went to go make coffee this morning and discovered a nasty surprise.
He'd forgotten to clean out the filter.
It was full of soggy used coffee grounds, and something green and fuzzy, which managed to coat the entire filter overnight.
Upon dumping the filter, he unwittingly unleashed a plague of 8026 fruit flies which are now darting about my kitchen, and taunting me with their flying manoevers.
Last time I checked, coffee was not considered a fruit - heck, despite the fact that it comes from a bean, it's not even a vegetable, so why this torrent of fruit flies? Surely they aren't trying to get a caffeine fix are they. I suppose if my life was only 24-36 hrs long, I'd not want to waste any of it sleeping either.
Still, they are annoying me, so I ran around searching for the fly swatter.
It was in the kids toybox - one of their favourites.
I proceeded to whack the living daylights out of my oak cupboards, and anywhere else a fly may have landed. Wasn't too hard at first - there were so many, I was getting 2 at a time.
Fruit flies, in addition to being really stupid - are not really all that fast. You can catch them in midair if you're fast enough.
My problem is that their true talent of reproducing faster than rabbits on crack is making it such that I no longer kill one, but 3 more reappear and hover around. It's a never ending battle. And there's always one that flies straight into your face. I want that one gone.
If you don't get them all, the remaining 2 will find each other and inevitably spawn a whole new generation tomorrow.
This means war on fruit flies.