Charlie Brooker has some suggestions about lying for fun
Text a friend at random saying: "Wahey! I'm in a HELICOPTER!" Someone did this to me once; it worked a treat. Try it now. Go on.
You and a friend are listening to an unfamiliar song on the radio. Before it finishes, say, "I can't believe this is Charles Dance - the man's lost his mind", then maintain that it is Charles Dance, it really bloody is, honestly, you read about it somewhere. Keep the pretence up as long as you can, despite their protestations, even if it's a woman singing. Say he's recorded it for a cow charity. Get angry if they don't believe you. They will eventually. They always do.