Model railways essentially, plus interest in the real thing. I belong to a society that owns three real 1:1 scale ex-British Rail locos that are hired out to work on the network.
Music - listening only as unfortunately I have no musical ability at all, therefore
Hi-fi - Equipment as high end as I can afford, with the emphasis on vinyl.
Car modelling and cars I owned a Triumph Vitesse Saloon Mk II 2-Litre for 11 years and did a lot of my own maintenance. Modern cars are too complex!
Also read a lot, and have what could be called a secondary interest in photography, bird watching, cooking (vegetarian only), aircraft and gardening.
Used to play a bit of football (soccer to the US readers) and squash but not for some years.
As has been said, it's easy to talk to anyone who models in any genre, as they are usually on the same wavelength.
steve