 A fair coin is tossed. If it comes up heads, you receive $2. If it comes up tails, the coin is tossed for a second time. If it then comes up heads, you receive $4. If it comes up tails, the coin is tossed for a third time. If it then comes up heads, you receive $8. If it comes up tails, the coin is tossed for a fourth time. And so on. We continue until the coin comes up heads. If this takes n tosses, then you win $\(2^n\).