Knock knock. Who's there? Europe.

Europe who? You're up for a pun-tastic time, aren't you? Because 'Europe' for a treat, if you catch my geographical drift!

Knock knock. Who's there? Sew

Sew who? Sew long, I've been trying to weave a good joke.

Knock knock. Who's there? That's what I'm asking.

That's what I'm asking who? That's what I'm asking who wants to know who's on the other side of this door!

Knock knock. Who's there? Water.

Water who? Water you waiting for, open up!