What occurs twice in a week, once in a year but never in a day?

Jim and Sarah are in a long-distance relationship. Jim buys an engagement ring for Sarah and wants to mail it to her. Unfortunately, the only way to ensure the ring will be received is to place a lock on the package. Jim has locks and Sarah has locks, but neither has keys for each other’s locks. How can they make sure the ring isn’t stolen?

On a special event at the prison, 5 prisoners John, Jacob, Krist, Tang, and Dang given a chance to go to a sauna and can bring one thing with them.

Following are the things that the prisoners bring with them.
John: A soda
Jacob: Thermos
Krist: Book named "How to kill"
Tang: A Walkman
Dang: Harmonica

Since it is a Sauna, no one can see each other. After a while When the steam is switched, Tang was found dead and there was blood all around.
J Bond was called and he instantly come to know who can be the murderer. How?

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

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

A shepherd had 18 sheep, out of which, all but ten died.

Can you tell us how many sheep was he left with?

During which month do people sleep the least?

If in a car race, the man who came two places in front of the last man finished one ahead of the man who came fifth, how many contestants were there?

What has a bottom at the top?

Forwards I am heavy, backward I am not. What am I?