I am well into my 40s. We don't have wild excitement every weekend, but still do a fair bit around work and DC commitments. We were at Def Leopard the summer before lockdown and I had AC/DC tickets for last summer as my Christmas present that Covid cancelled, and I like to get to a wide variety of musical events of different sizes when I am able. And theatre and cinema.
We go hiking a fair bit and have various other outdoor adventures. I only started to learn to sail once I was already in my 40s, and my 40th birthday adventure was our first ever ski trip (we plan to go again but Covid had hit plans on us 2 seasons now).
We enjoy going out for nice meals as a couple or with friends. Our neighbourhood is particularly friendly and we do a number of BBQs/drinks/Christmas party etc over the course of most years, often going late into the night (and many evenings having started as a 4pm text "anyone fancy a glass of wine while it's nice?").
We like to travel, but having a lot for work, and having various commitments at weekends (I am a Cub Scout Leader for the Saturday pack, DD has various sports trainings for a few teams and different sports, etc) we don't tend to do too many weekends away right now - but will get back to more city breaks once DD has got some independence (i.e. learned to drive in 18 months) and I get some extra Leaders.
Yes, some of my fun is dancing around the kitchen, gardening, crafting of various sorts etc., quieter activities. But definitely not a case of "life stops dead in your 40s". DH and I are not sitting around for hours every night just watching tv.