You can open a practice account on TD Ameritrade
theres tons . you could even download the app " stock wars " which is lots of fun and realistic . I do wish they gave us less money to start out with though not everyone has $100,000 to start trading with. ( it would just make the game more challenging and realistic .)
Options house and option press both have virtual accounts. Option press even allows you to virtually trade commodities.
most online brokers let you practice using a virtual portfolio before you progress to the real thing.
Why play around when you can open an online account and play for real.
www.icicidirect.com ..demo virtual account
Something like what Optionhouse and Optionexpress has. With playable money and real time stock markets
