Eight of us go fourth, not back, to protect our king from an attack. What are we?

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.

Which is heavier: a ton of bricks or a ton of feathers?

Can you find the missing letter in the sequence?
S - T - I - L - ? - T - F - Y - C

What does the below image rebus riddle means ?

Name a key which is hardest to turn.

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

Outside a tattoo artist's shop, there was a signboard which read 'I make tattoos on only them who do not tattoo themselves'.

Reading it what do you think, does the tattoo artist tattoo himself?

I can be cracked, made, told, and played. What am I?

What runs around the whole yard without moving?