These crack me up everytime:

Aroo - A sound made when someone says something to grab your attention... kind of like "what?" except you go "Aroo?"

Blamps - A combination of both stomach cramps and bloating. Usually expressed by women in conversation, "How are you feeling today?", "Not great, ive Blamps."

Blunderguff - A fart let off just before a beautiful woman walks into the vicinity.

Fruluck - When you open a yoghurt and it splats all over you. The stuff that hits you is fruluck as well as the whole experience.

Hoddledehoy - An awkward, gawky youngster existing somewhere between a man and a boy.

Moo Point - If something is un-important for the time being it is a moo point.

And as i personal touch, for some perculiar reason, the word Dandelion causes me to laugh until i cant breath.