rules to a game:
You flip a coin. If you get tails you win 0.  if you get heads, i give you 
$1.  Keep flipping until you get a tails, at which point you walk away with 
the money.  however, each heads you get after the first you double your 
money.  So if you flip heads 3 times and then tails, you get $4.  What's you 
bid/offer on playing this game?  (would you pay $.5 to play? $1? $2?  what 
you charge me play against you?)