What does that mean? what is the difference between an open and closed game

From my understanding a closed game is a term used to describe a game in which most of each player's opening piece development takes place behind there own pawn structure. An open game is the opposite, a majority of the pieces are developed outside of the player's pawn structure. There may be a more specific definition.

Open games are tactical and feature aggressive piece development, early (pawn) tradeoffs and opening of files. Closed games are positional and focus more on the placement of pawns, closed structures and long-term tension. Generally, games with 1. e4 tend to be open and games with 1. d4 tend to be closed, though there are exceptions.

Thats what I needed to know.  Another question: I seem to get into alot of closed, 1 d4 games, where all the pawns are gridlocked  and nobody can do anything.  Are there any good gm games I should look at to figure out how to play these positions?

knights are better in closed, bishops and rooks in open, knights can jump

You can go to chessgames.com and look at Queen's Pawn games.

Here's a good (strange i know)  article in Wikipedia http://en.wikipedia.org/wiki/Pawn_structure that may help you devise a plan for different pawn structures. Anything with "chain", "wall', or "closed" in it would likely be a closed game.