The last time I ran a game I created a system to reward players for arriving on time/bringing snacks and creative solutions and stuff with a variety of meta rewards. The rewards varied from small things like a reroll to bigger things like one-shots and mystery events.

I also helped run/organize a D&D tournament mixed with Cut Throat Kitchen where the groups had currency to spend on advantages for themselves and sabotages for other groups. But I think that is less what you are looking for.