Pogs were round pieces of card, just slightly bigger than a two pound coin, with pictures on one side. Pogs were actually part of a game but were commonly used as playground currency in the same way as trading cards or marbles.
All the Pogs had different numbers on them and Pog collectors would try to build a complete collection including every Pog number available. As well as the official Pogs there were also a whole range of other unofficial Pogs on the market making Pog collecting incredibly difficult.
There were various different types of Pogs including shiny Pogs and special Pogs called 'slammers' that were thick black discs used in the actual Pogs game.
To play the Pogs game you placed as many Pogs as you wanted facing upwards in a stack and then with the 'slammer' Pog you would hit the top. All the Pogs that fell face down were taken out of the pile and whoever had the most Pogs at the end of the game would win.
I remember having many, many Pogs. In fact I had so many I had special Pog folders for them all. Basically the Pog folder was a ringbinder with special pockets in it just the right size to put your Pogs in. I also had a large Pog tube full of Pogs! There were hundreds of them and I don't know were they all went... I seem to have misplaced them... :(