What begins with T, ends with T, and has T in it?

I am a type of word that is spelt incorrectly or used differently, on purpose for humour. What am I?
Hint 1: You can find me in a joke.
Hint 2: I am a play on words.

I know a country, If you remove the last alphabet of its name, it will become a part of your body. Do you name it?

A red house is made out of red bricks. A yellow house is made out of yellow bricks. And, a blue house is made out of blue bricks. So, what is a greenhouse made of?

Why is a river so rich ?

how come the second man dies?

Can you start the fire using two pieces of wood?

James bond was pushed out of an aeroplane without any parachute.
He survived, How come?

Why do people go to bed?

What do you get if you add 2 to 100 four times?