I'll try to explain how to play...hope it makes sense.
Each person has their own deck of cards. You start with 4 discard piles and a stack of about 13 cards called your Nerts pile. Like Elizabeth said, you play your aces in the middle and anyone can play off of them, like in Double Solitaire (but on a bigger scale).
The point is to get rid of your Nerts pile. You can only play the top card of your Nerts pile, either into the middle or into one of your discard piles. You go through all of the rest of the cards in your deck, one at a time, and play those into the middle or into your discard pile. Everyone just plays all at once, as fast as they can, and as soon as someone gets rid of all the cards in their Nerts pile they yell "Nerts!". You separate the crads everyone played in the middle. You get points for each card you put in the middle and you lose points for each card left in your Nerts pile.
I'm not sure if you wanted such a lengthy explanation.
Hope it makes sense!! It really is a LOT of fun.
Sarah