Sometimes we already do things like this in games, like removing the limit on how many times you can tap the ball on one side in Volleyball, when we play them with friends. I think that using rules like that make it more fun. Conversely though, loosening up rules might make games less fun to watch.
Also, this is a really good question!
Other rules for example:
Adding the ability to accumulate debt in Monopoly. (This can lead to some... unorthodox strategies)
Variable game length depending on how much time you have is a useful one. (This one might make sports hard to watch though.)
Sometimes we already do things like this in games, like removing the limit on how many times you can tap the ball on one side in Volleyball, when we play them with friends. I think that using rules like that make it more fun. Conversely though, loosening up rules might make games less fun to watch.
Also, this is a really good question!
Other rules for example:
Adding the ability to accumulate debt in Monopoly. (This can lead to some... unorthodox strategies)
Variable game length depending on how much time you have is a useful one. (This one might make sports hard to watch though.)