G'day frogprince,
I don't have a piccie but can supply a description until someone else displays one.

Picture a tinselly paper cylinder about 12" long and 1.5" diameter, with a twist about 3" from each end; between the twists there is a thin cardboard cylinder (~ 6" long) inside the cellophane and tinsel. Inside the central cardbaord cylinder is where the paper hat, paper slip with woeful joke, and/or sometimes a toy or even even a fortune cookie.

Distal to the twists at each end is the "handle" part of the cracker, with a narrow strip of cardboard through the whole length of the cracker; this strip is connecting a bit of 'explosive' powder. You and your partner each grab a handle and pull firmly away from each other; the assembly usually separates at one of the twists, leaving one of you "the victor". As the cracker separates the two thin strips of cardboard, the powder gives of a sharp (but small) bang; hence the name "cracker".

Cheers, Rowan