What other Hobbies or Interests Do You Have?

Too many hobbies!

High end audio - based in both digital and analogue, I still have a main system, an electrostatic speaker based system, a system made up of some of my old gear I can't bring myself to get rid of, and even a system in my library albeit a modest one.  Server drive with c. 3500 digital albums ripped by me, and a bit more than that number of vinyl LPs.

Wine - wide ranging dedicated cellar with almost as many bottles as LPs.

Cars - raced them for 30 years (still have my old race car, a 58 MG) plus a couple of other period MGs, a Jensen, and a couple of modern sports cars (Solstice, BMW Z4MC), Sold another Jensen and an old Lamborghini when I downsized.  Used to build and restore them, but not so much over the last decade.

Gardening - c. 300 species Rhododendrons (down from 800 at the old place) plus many Magnolias, Acers etc. 

Cooking - a natural meld with the wine interest

Clocks and watches - keep and restore a wide range from late 1600s on.

Fountain pens - used to use a different pen or two every day when working, less often now retired.

Antiques - furniture etc.

Photography - both botanically related and otherwise. Still have my first underwater camera (60s vintage) so tend to hang onto gear but did acquire a DSLR recently to replace a couple of fixed lens digitals.

Enough to keep me out of trouble.

Yes I have another Hobby but it carries a dirty little secret
I do part time DJ' ing but have to connect up to some pretty lousy pre installed Amps and Speakers.
My dirty little secret is I try all sorts tweaks and workarounds to get the best possible sound without the dancers realizing
I say on average only 3-5% of dancers will notice the difference between
a mediocre sounding track and one thats been enhanced by software or hardware tweaks

Great thread! Diverse crowd, but with certain themes recurring! My love of music and audio equipment comes from my parents, who always had a stereo system, and lots of LPs spinning. 
As for me... I’ve been lifting weights for 41 years straight, and have been competing in bench press competitions since I was 31 (I’m 54 now). I have my own home gym where I mostly powerlift, and my sons, and my grandkids, join me whenever they’re over. 
Speaking of grandkids, is being a grandfather a hobby? If so, that’s my number one! I also love grilling all year on my Weber kettles. Big family, so plenty of grill time all summer by the pool. 
I have a 2015 competition orange mustang GT premium with the “50 Years” package. I’ve had a thing for mustangs since I was six! I’m not a mechanic, but I can detail like crazy!

I also keep aquariums. Big oddball fish interest me. My favorite is my silver arowana. Close second is my datnoid. We’re getting a 300 gallon tank for them this year. 
My wife is very patient with my audio hobby, so I’m sure to remember to ask her what she feels like hearing each night. We have a main system, a bedroom system, a family room system, and a vintage system in my weight room! As well as a system in the shed which plays outdoor speakers aimed at the pool area. There’s almost always music playing around the house. And I make sure it sounds good!

Keep it coming!!

Classic car collector.
Guitar builder.
Beekeeper.

vivisection...mummification...alien communications...petty larceny

OK, none of that is true. The truth is so boring:

1 - I walk 5 miles a day as fast as possible. Ran that or more for decades; now it's walking. Used to swim 2-3 miles/day (that was then).

2 - Music every waking hour: usually streaming classical interspersed with headphone audio of many different genres (I have 7 headphone amps and 8 or 9 headphones...it's not a passing phase)

3 - Streaming video content (4K blu rays & Netflix) on a huge OLED TV. I've always been a fan on high quality visual narrative, and we are the new golden age of that

4 - And writing...anything & everything. I make my living as a writer, but even when there's no work, I write for other reasons. It' what rat psychologists call "consumatory behavior" (ie, do it because it feels good)