In The 1st month of this year(the year 2013), I noticed that the date 13-1-13 (13 January 2013) is special.

This date is special as:

Date * Month = Year.

Can you figure out which year of this century has a maximum number of such dates?

One is to three as three is to five and five is to four and four is the magic number.
What is the pattern?

When I go in I might cause pain. I cause you to spit and ask you not to swallow. I can fill your hole. What am I?

What 8 letter word can have a letter taken away and it still makes a word. Take another letter away and it still makes a word. Keep on doing that until you have one letter left. What is the word?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

What kind of band never plays music?

These types of puzzles are known as charades. What you have to do is find two words that are referred to in the first stanza and the second stanza and put them together to form the third word in the third stanza.

Just for example, if my first refers to 'off' and my second refers to 'ice', then my whole will be office.

My first is present - future's past -
A time in which your lot is cast.

My second is my first of space
Defining people's present place.

My whole describes a lack of site -
A place without length, breadth, or height.

10+10 and 11+11 can give you the same answer.

Explain how?

There was a man he lives in a hotel each morning he presses the first floor button each evening if there is a person in the elevator he asks him to press the 10 floor button if there is no one in the elevator he takes the stairs why.

A clock loses 10 minutes each hour. If the clock is set correctly at noon, what time is it when it reads 3 PM?