Talking about what is exciting for me

Hi everyone!
I have to writte a letter talking about something exciting I like to do.
I need your help for the mistakes. Thank you! :)

"Hi John,

Thanks for your letter - it was great to hear from you.
What is exciting to do for me? Well, what I most like to do the most is practice sports. I usually practice three kind of different sport.
I go to the gym at the Alcañiz's sports centre three days a week. After that, I go swimming. I also go to run through the path next to the river on the at weekends.
I love sports because they it keep you healthy and fit. Furthermore, it's something fun and it allows you to elimante stress, so later you feel relaxed.

So that's what is* exciting to do for me.
Don't forget to write back soon again.

All the best,
Iván"

Very good, but I would also say which sports in the letter.

*In this sentence, we would say "what's" instead of "what is". They're both correct, but "what's" is more common and sounds more natural. 

Talking about what is exciting for me

Hi everyone!
I have to writte a letter talking about something exciting I like to do.
I need your help for the mistakes. Thank you! :)

"Hi John,

Thanks for your letter - it was great to hear from you.
What is exciting for me to do? Well, what I like most to do is  to practice sports. I usually practice three kinds of sport.
I go the gym at the Alcañiz's sports centre three days a week. After that, I go swimming. I also go to run through the path next to the river at weekends.
I love sport because it keeps you healthy and fit. Furthermore,( too formal for an informal letter. I would say "also") it's something fun and it allows you to elimante stress, so later you feel relaxed.

So that's what is exciting for me to do.
Don't forget to write soon again.

All the best,
Iván"