I See the Moon in the Spoon
Source: Leon Van Oldenborgh at The Overkill Festival 2022
One player comes up with a secret action, then holds a spoon (or other prop) up to their face and says the magic words "I see the moon in the spoon".
If, while the saying the magic words, they were also performing the secret action, they follow up by saying "...and I do see the moon in the spoon". If they were not performing the secret action, they say "...but I do not see the moon in the spoon".
Players then take turns, taking the spoon and repeating the magic words, while trying to guess the secret action. If they are successful the first player will confirm by saying "You do see the moon in the spoon"; if not they will be informed by the first player that "You do not see the moon in the spoon".
In our game, Leon's secret action was to say thank you to anyone who passed him the spoon. Embarrassingly I did not guess the secret action and had to be told what it was.