Find the Next Number in the Sequence

2 9 3 1 8 4 3 6 5 7 ?

Why is the Hole below a Lock?

Nine marbles are arranged in the image below. Can you slide two marbles to form a square?

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?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

Your last good ping-pong ball fell into a narrow metal pipe embedded one foot deep in concrete.
How can you get it out undamaged, if all the tools you have are your tennis paddle, shoe laces, and plastic water bottle, which does not fit into the pipe?

You can win me and lose me but never buy me
You can not eat me and never want to part with me
I can make you cry or bring you joy
I am not a machine and definitely not a toy
You keep me but i am not forever just yours
You might find me in a case or on a shelf next to a vase
I am hard and i am tall if you bump me i am sure to fall
I am made of different materials and am at many events
If your lucky and fight hard I might be yours
What am I ?

What three numbers, none of which is zero, give the same result whether they’re added or multiplied?

Two in a corner, one in a room, zero in a house, but one in a shelter. What is it?

After a heavy Thanksgiving meal, the night watchman went to work. In the morning, he told his boss he had dreamed that a saboteur planted a bomb in the factory and that he felt it was a warning. The boss promptly fired him. Worker confused, Why boss fire him?