Hi-fi, old school...turntables and such (listen/evaluate).
Classical music recordings (collect/listen/critique)...mainly analogue LP but also CD -- this has waned recently as I've increased interest in folk/songwriter genre.
Songwriting.
Etymology.
Comparative religion studies (esp. esoteric: Vedas, yoga, Sophia/perennial philosophy, Kabbalah, Sufism, Gnosticism, et al.).
And the most time-intensive activity: my wife's honey-do list.
Dirk