How do you kill flies at your house?

We had a bit of a fly problem, but we took care of it.

Why all the flies you ask?  Well the other day, Andrew body slammed the screen door, bending it severely, and is has never been the same.  He couldn't just walk into the house, but wanted to take one leap from the edge of the step into the house, forgetting the one detail of checking whether the screen door was open or closed.  It was closed.

So anywho... the screen door doesn't really shut, and the flies help themselves in.  But we figured out how to deal with them.