Ever run a marathon? I know it sounds daft but I know a bunch of people who don't need to work any more, and they all got into triathlons, Ironmans etc. They're all crazy about it. They usually have 2 per year but there's plenty of small events during the year that fill up the calendar. It's a social circle, a fitness club and a support group. My brother in law has been part of that scene for years, and after my sis died a few years ago, they helped pull him through it, hauling his ass out for runs and cycles. He even gets business through it.