Good luck

In the same way that it is good luck to find a 4 leaf clover, in some countries it is good luck to witness a car crash, an event that you will not see many times in your life. Witnessing your own car crash however is not considered good luck though, for obvious reasons.

Yodaism

Yodaism is a speech impediment whereby the afflicted speaks like Yoda.

I've recently found out that some people actually want to speak like this!
http://www.yodaspeak.co.uk/index.php

...and it seems to be called Yodish.

Keyboard

If you press all the keys down on your PC keyboard at the same time you get a special character that no one has ever seen.

Baileys

It's impossible to drink more than a pint of Baileys.

Tea

Tea made with urine is colourless.

Eraser

You can't write on a pencil eraser with a pencil.

Cereal dust

The dust in the bottom of cereal packets is carcinogenic.

Bath plugs

Most peoples' bath plugs are attached to their bath by too much chain. If this surplus chain was removed and joined together then the chain would stretch over 3 times round the earth.

Headphones

Some people cannot wear in-ear headphones as this awakens a prehistoric fear that they have a newt crawling inside their ear.

Santa...

...can travel faster than the speed of light.

Wind

If you fart lying down it doesn't smell.

Christmas

90% of people hate Christmas. And a staggering 86% of people don't believe one can have a virgin birth.

20% of people aged 23 and over still believe in Santa, I was shocked that 80% don't and I'm 36.

Cold feet

It's impossible to go to sleep unless your feet are at the same temperature as your head.

Birth

A staggering 30% of most people can remember being born.

Accents

People who have regional accents can't mimic other regional accents.

Blood pressure

Removing blood from yourself can effectively lower your blood pressure. Obvious really!

Wet

If you put the hand of someone who is asleep in a bowl of water then they'll wet the bed.

Trying this on your young children is non-conclusive as they wet their beds anyway, but it can be just as much fun.

Spiders

The number of miles crawled accross your face when you are asleep by spiders is on average 0.75 per year!

Finger in drill

If you tighten your index finger in the chuck of a handheld drill and get someone else to hold the drill, after applying power to the drill eventually you'll do a somersault.

A Googolplex

...is a number and there aren't enough atoms in the universe to write down this number in full! Actually this might be true, so perhaps not a candidate fict.

One from my childhood...

If you chew chewing-gum for long enough, not only does it get its flavour back, but it changes colour too!

Dot-to-dots

If you joint the dots up in reverse order, you get a different picture.

If you only join the prime numbers up you always get a straight line, this is called Dot's law named after Dot, who discovered it.

If you join the dots in a random order then you get a random picture.