Quick skit

Hubbs reminds me every day to shut the back door, otherwise the flies get in. So, without further ado:

Couple come home with shopping bags in each hand, leaving the door open.
He: Did you shut the flywire door? The flies are bad today.
She: I'll do it in a minute.

They start putting groceries away, when in walks a human-sized fly (bloke in a pathetic costume, bit Mick Molloy-ish)

Fly: Afternoon all. Lovely day. (goes around the room and touches everything, puts his hands on some fruit in the bowl).
He: How did you get in?
Fly: The door was open! Honestly you people, what do you expect?
She: Yes, yes, yes, I'll close it now before any more get in.
He: (checking groceries) We didn't buy any fly spray, either.
Fly: (goes into loungeroom, sits on the backrest of the sofa, makes himself at home.)
She: I don't know why you get so upset darling, it's just one fly.
He: Yeah, but they get on everything. They make me sick.
She: We're both tired, let's have something to eat.

(They sit down on the sofa to eat their sandwiches, the fly sitting behind the bloke, the fly falls down across the man's lap)
He: Oh bloody hell, it landed on my lunch!
She: It's just one fly darling!

.... you get the drift. Loads more possibilities, what with the big blowie being a "fly on the wall" while they're having an argument or having sex; the fly jumping into an enormous prop salad bowl "The fly got on the salad". etc etc.