What is the riddle which can be asked all day with a different correct answer each time.

Replace the question mark with the correct number below.

I have teeth but i don't bite. Who Am I ?

There's a day, that comes around once a year.
To celebrate the man, you hold dear.
He gave you life, love and will pick you up if you fall.
When it comes to guys like him, He's the best of all.
Who is he?

2, 3, 5, 9, 17, _ What is the next number in the sequence?

A man in a car saw a Golden Door, Silver Door and a Bronze Door. What door did he open first?

If 1+9+8=1, what is 2+8+9?

It belongs to you, but other people use it more than you do. What is it?

There are three houses in a straight row. One is red, one is blue, and one is white. The red house is left of the middle. The blue house is right of the middle. Where's the white house?

A high school has a strange principal. On the first day, he has his students perform an odd opening day ceremony:

There are one thousand lockers and one thousand students in the school. The principal asks the first student to go to every locker and open it. Then he has the second student go to every second locker and close it. The third goes to every third locker and, if it is closed, he opens it, and if it is open, he closes it. The fourth student does this to every fourth locker, and so on. After the process is completed with the thousandth student, how many lockers are open?