Hot Potato is a mobile phone game for multiple users based on Bluetooth proximity. The purpose of the game is to earn points by handling as many "potatos" for as long as possible. While a player is holding a potato, it heats up, and the player has to pass it on to another mobile phone in the vicinity to cool. If this person is another player, he or she can throw the potato back to "burn" the person who passed it on. If it is a non-player, he or she is oblivious to the potato and may walk off with it. The "Hot Potato" game illustrates how the presence of other people - whether or not they are gaming - can be used to create a rich and dynamic game experience, but also highlights the ethical issues involved with this. It is freely available for download at the project web site.