I always found the game of Guess Who to be a little to easy. As an adult I have made adjustments to the game to 1. Involve drinking and 2. Allow room for interpretation. In my version you cannot ask questions based on physical characteristics but rather questions based around what you assume about their personality and back-story. For example, questions could be.
Does your person look like he would ever run for political office?
Is your person a cross dresser on the weekends?
Does your person have daddy issues?
Would you say that your person most likely has a fruit allergy?
Granted with this version you may not have the same person at the end, but if you do it is amazing and if not you still have a grand time because you are drinking throughout the entire game.