Can you find out the next digit in the following series ?

0, 0, 1, 3, 2, 6, 3, 9, 4, 12, 5, ?

What number divided by 4 is the same as that number minus 4?

You board a train. The train will have to enter a tunnel soon. You are claustrophobic. Which place is the best for you to sit?

Dr Doom invited a group of puzzle fanatics to a party which was oriented toward having puzzle-oriented games. At night, he introduced the guests to a 'unique riddle'. A prize was offered to the one who solved it first.

The guests included six people named Tom Paul, Fox Obama, Jeremy Reener, Alex Murphy, Prim Pastor, and Ellen Page. The winner of the 'unique riddle' contest was to be announced after the dinner. So Dr. Doom stood up and started the announcement:

'Okay now everybody!'
'The winner of�'
'The Hardest Riddle Ever Event'

But before he could complete it, the light went out and his voice was not heard without the mic by anyone. But they already knew who the winner was. Can you deduce the name of the winner?

Can you find out which number multiplied by itself will give the output as 12345678987654321?

A rubber ball keeps on bouncing back to 2/3 of the height from which it is dropped. Can you calculate the fraction of its original height that the ball will bounce after it is dropped and it has bounced four times without any hindrance ?

It is a six-letter word.
The first four letters are me.
The second and last letters are the same.
The fourth second and last letter is payment.

Who is it?

What has many keys but can’t open a single lock?

What has 88 keys?

What is the Surname of Barbie Doll?