Why do people go to bed?

The answer I give is yes, but what I mean is no. What was the question?

There's one "sport" in which neither the spectators nor the participants know the score or the leader until the contest ends.

What is it?

Take away the whole and some still remain. What is it?

A Man gave one of his sons 10 cents and another son was given 15 cents. What time is it?
Hint: Figure out the relation between time and number, is not so easy..:)

A mile-long train is moving at sixty miles an hour when it reaches a mile-long tunnel. How long does it take the entire train to pass through the tunnel?

In the Chess Board picture below white army is arranged. You need to add a black army on the board such that no piece is under any threat.
Note: Army comprised of 1 king, 1 queen, 2 rooks, 2 bishops, 2 knights, and 8 pawns.

I am the black child of a white father, a wingless bird, flying even to the clouds of heaven. I give birth to tears of mourning in pupils that meet me, even though there is no cause for grief, and at once on my birth, I am dissolved into air. What am I?

What is in seasons, seconds, centuries and minutes but not in decades, years or days?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?