Get a large aquarium!
Nice indoor hobby- you can use your creative side in landscaping and planting out the tank, read lots on biology for maintaining the system, all you have to do is sit back and enjoy watching your hobby (so relaxing!) and depending on how large the tank is, can even keep you a bit fit with all those buckets of water change water you have to carry and dump.
And, if you get livebearers, there easy to breed and so much fun to watch baby fish.
When the weather is no good for astronomy, I go and play with my fish tank indoors, as there's always something to do in it (plant pruning, glass cleaning etc.) Also brings a lot of joy seeing the fish when they are happy and playful and breeding lots.
Also Mel hit the nail on the head with those short films seeing as you write stories.
You could be a big youtube star
.
And if you decide to get fit, just remember if you put too many big muscles on you with being around 6ft odd tall, yer might scare me next time I see you.
I think it's a great idea- go join a gym and also meet some girls while you're there (two hobbies in one
).
And by the way.. I would have thought chasing girls is a hobby in itself at your age.
, You're good looking, go get them tiger grrrrr.