Stock-Trak
Stock market game where you simulate managing a portfolio of stocks, bonds, mutual funds, options and futures. Test an investment idea, learn about the financial markets, or develop a track record.
http://www.stocktrak.com/

Fantasy Stock Market
Free, fun and educational investment game. Trade stocks and mutual funds with $100,000 in fantasy money. Portfolios are tracked and ranked for monthly prizes. Perfect for the beginning investor or professionals.
http://www.fantasystockmarket.com

Foresight Exchange
A notional stock market where you buy shares betting on the outcome of future events.
http://www.ideosphere.com/fx/

Blogshares
Fantasy weblog stock game, where weblog value is based on hits and links.
http://www.blogshares.com/

The Great Game
Equity trading on the London Exchange. Free prizes for the best performing portfolio each month. Direct links for research and analysis.
http://www.thegreatgame.com/

Xodds.com
Offers fixed-odds financial betting with either virtual or real accounts.
http://www.xodds.com

U.S Idea Futures Exchange
A free web-based futures market.
http://www.usifex.com

Xycoon Online
Virtual stock exchange. Free simulated trading.
http://www.xycoon.com

Wall Street Raider
Windows based investing game. Includes information and download links.
http://www.roninsoft.com

BullBearings
A free UK based investment website featuring fantasy stocks and virtual financial spread betting.
http://www.bullbearings.co.uk/

TradersGame.com
Option market simulation. Derivatives pricing calculators for treasury managers, hedgers and traders.
http://tradersgame.com/

MockTrading.com
Free mock commodity trading.
http://www.mocktrading.com/

Case Game, LLC - urladex
Trade virtual shares in web sites based on their Alexa traffic rating.
http://www.urladex.com

Virtual Stock Exchange
Stock market game and message boards. Trade stocks and funds in a collaborative environment. Run your own competition or join others.
http://vse.marketwatch.com/Game/Homepage.aspx