I haven't been on my mountain bike since I let it go with the weight these last few years, but slowly getting back there. Paid way too much for that thing to let it sit.
Huge fan of riding mountain bike trails. Both mountain bikes and dirt bikes, never gets old. (Even though I do!) I feel Streifenkarl's comment. Always looking for that thrill again, but have to be realistic with the age.
Here's a free date or marriage tip for you if it applies. My wife never learned how to ride a bike. But I found that on tandem bikes, as long as the lead can ride it, it's all that matters. The second person is literally just there for more pedal power.
So when we would go on vacation, from beaches to woods, wherever we found bike trails and tandem bikes for rent, would do it, and my wife loved every second since she never got to experience it.