What do you do when your Sim(s) are stinking rich?

Wow that's something. I don't actually have any that rich sims. I play rotationally so the progress is slow and also I usually find a way to get rid of their money, for example kids not inheriting any of it. I like playing poor. I was going to suggest moving into a bigger house and buying a retail lot/restaurant/vet clinic and improving it. That's what I plan to do if my sims get too some extra cash.