Can you start the fire using two pieces of wood?

What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?

The day before yesterday I was 25 and the next year I will be 28. This is true only one day in a year. What day is my birthday?

What four weights can be used to balance from 1 to 30 pounds?

What is the next number in this matchsticks series riddle?

What do you answer even though it never asks you questions?

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

You are given 16 witch hats. The hats are divided in four different colours – red, blue, green and yellow. Every colour has been assigned to four hats. Now each of the hat will be glued with a label of an arithmetic sign – ‘+’, ‘-‘, ‘x’ or ‘/’. But you can label one sign only once on one colour. In such an arrangement, the hats can be uniquely defined by its colour and symbol.

Can you arrange all the 16 hats in a 4x4 grid in a fashion that no two rows and columns have a repetition of colour or sign?
We have arranged four hats in the below picture to assist you.

After teaching his class all about Roman numerals (X = 10, IX=9 and so on) the teacher asked his class to draw a single continuous line and turn IX into 6. The teacher's only stipulation was that the pen could not be lifted from the paper until the line was complete.