the one where you tie and blindfold the lee and tickle for 30 secs, then ask if they wanna continue, then double the time, then repeat this process and see what they say when you start getting to time like an hour and 4 mins, 2 hours and 8 mins etc,
Then swap place and try to beat the time.
A nice twist I put on it is the person who looses has to endure non stop, the maximum time acheived by the other player who won 😀