Quote from L. Ron Hubbard‘s book The Way to Happiness, precept – “Be Industrious”.
The easiest way I’ve found to keep my kids happy is to keep them doing something which they feel is “helpful work”. It’s only when they’re idle and looking for a game to play that the game then becomes “hitting each other” or destroying the house or some such. As such, it’s one of my wife & my top priorities at all times to have a good, long list of things that can be done in any weather to keep them active and industrious.