Here's something I've been working on. The dialogue needs a bit of polishing at the minute, but that's work in progress for you.
Int. Kitchen
James is sat a table reading the paper. Lucy is cutting some vegetables up.
James: Is your sister still coming round for dinner?
Lucy: Yep. And she's bringing a man!
James: She's finally got a boyfriend?
Lucy: And he says he knows you.
James: What's his name?
Lucy: Tom Fleet?
James: Jesus Christ!
Lucy: D'you know him?
James: Yeah. I was at primary school with him.
Lucy: What was he like?
James: A little dickhead. He used to run round pretending to be a spitfire all the time.
Lucy: I'm sure he doesn't do it anymore.
James: He better bloody not.
CUT TO: Int. Hallway
A doorbell rings. James opens the door and Sandra (Lucy's sister) enters.
James: Hey Sandra! You alright?
Sandra: I'm fine thanks.
James: Where's your new man?
Sandra: He's just parking the car. Here he comes.
Tom runs through the front door with his arms outstretched like wings and making plane noises. James sighs.
CUT TO: Int. Dining Room.
James, Lucy and Sandra are sat at a table 'post-dinner'.
Lucy: Well I'm going to vote for whoever sorts out immigration.
Sandra: I don't think they'll ever sort it out.
James: The problem is that they need to-
Tom comes running into the room and round the table impersonating a plane. He then 'flies' out the room.
James: Does he have to keep doing that?
Lucy: Let him be.
Sandra: Don't you like him?
James: He keeps interrupting me and-
Tom 'flies' in the room again and up to James.
Tom: GERMAN! (MAKES MACHINE GUN NOISE) GERMAN! (MAKES MACHINE GUN NOISE)
Tom flies out.
James: You see!
Sandra: He's only having a bit of fun.
Lucy: Yes, James. (FIRMLY) Let him be.
Sandra: Anyway, about immigration.
Sandra and Lucy begin chatting. Tom 'flies' back in and keeps circling the table. Sandra and Lucy take no notice, but James becomes increasingly agitated.
James: You're 32 for God's sake!
Tom carries on flying. James stands up. He goes to hit Tom a couple of times, but keeps missing. Then he holds on to an imaginary machine gun. He starts 'shooting' at Tom. Tom begins flying round the room in a haphazard fashion.
Tom: Parachute! Parachute! It's stuck!
Tom nosedives to a heap on the floor. James smiles smugly. Sandra runs over to Tom.
Sandra: You've killed him.
James: He was being a dick.
Lucy: You're just a big bully.
Sandra: Yeah, why don't you grow up?!
James: Me grow up?! You must be joking!
James storms out of the room.
Lucy: Where are you going?!
James: Out!
Lucy and Sandra look at each other. A strange bouncing noise starts up. Lucy and Sandra look out of the patio doors and see James angrily bouncing on a spacehopper.
ENDS