When my father was 31 I was 8. Now he is twice as old as me. How old am I?

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.

Usually, a boxing match consists of twelve rounds. In a particular friendly match between two heavyweights, the match was finished in the ninth round itself as one of the boxers knocked out the other one.

But, in that fight, no man threw even a single punch.

How can this be possible?

Baseball bat and ball cost $100. If the bat cost $99 more than the ball, what is the cost of each?

If we change the South-East direction into North and North-East into West and all others similarly.
Can you find out which direction will be in the place of South-West direction?

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

John can fit six large chocolate boxes or nine small chocolate boxes into a carton. How many cartons will he require to put sixty-six chocolate boxes into?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

Can you identify the famous TV character from the rebus below?

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?