Snap?

Here's a simple card game for two players - you each have two cards, one red, one black.  You choose which card you intend to play, and put the other card away from you face down on the table.  You then each show the card you have elected to play.  If you both show red cards, you each win £1.  If one of you shows a red card and the other a black, the one who shows the red card wins £10 and the one who shows black wins nothing.  If you both show black cards, you both win £3.  The money comes from some philanthropic third party, so neither of you loses anything.  The game can only be played ten times, and you are not allowed to speak to each other until five hands have been played.  What should be your strategy?