20 Questions. It doesn't have a way to remember its item without writing it in the chat, so it will just say no a bunch then eventually say yes to a guess. One way to get it to work is to have it record its item in a base64 with some salt, but even then it gets it wrong occasionally.
If you provide the item yourself, you can let others play 20 Questions. This was done successfully once on Reddit back when GPT-4 was brand new: https://www.reddit.com/r/ChatGPT/comments/129j7ux/can_gpt4_k...
yes, base64 or chinese works better now but still only kinda.
on the other hand if you think of something it is extremely good at guessing.