Secret friend game is to make a gift to someone without knowing who it is not.
To prepare it, you need a lottery among all participants in which one partner is assigned to each participant is made; this is the invisible friend of your partner.
From this site you can do the draw, and every invisible friend you will receive an email with the name of the person who has to make the gift.
For that you have to follow these steps:
¯ Register a drawing
¯ Add participants
¯ Set draw
¯ Perform Sweepstakes
Adding participants can indicate their partners to tap into the draw not give the couple.