Hargreaves Lansdown has teamed up with Moneyam Corporate Solutions to launch The Big Deal, a "Stock Market Challenge" game where you make virtual trades in a wide range of real companies and funds. You can also create your own company and recruit other players to help build a winning team - it's up to you.
There are small(ish) prizes each month for the best performing individual and the best company. When the game ends on 30 May 2014, the best individual and company will grab a big cash prize.
There's also a monthly prize draw that you are entered into when you refer a friend.
The game is free to enter, and you aren't obliged to play it once you've joined. However, you will need to remember that you're not trading for real - so try not to get too excited when you back a winner! Likewise, don't let your trading habits in the game affect your real-life investment decisions. You will almost certainly be making high-risk trades in the game, and doing the same with your SIPP or stocks & shares ISA could be a BAD THING!
Above all, read the game's Terms and Conditions carefully before continuing.