Either Half-Dome hike when I was 9 (minus the rope climb) or 15-mile run during Cross-Country in high school.

Now I'm as unfit as can be while staying skinny.

Mr. Puggsly Winns!

That is quite an acomplisment!

Mine would be surviving all the times I nearly didn't.  Or maybe that time I pulled off a hexa-pirouette.

Was invited to a pro COD clan. (Black ops era)

Staying awake 25 hours.
It was during a trip I had with some friends.

I climbed Yosemite Falls like 4-5 years ago.

Started doing exercise by myself. No gyms, just the help of my father, my uncle and one friend, and they all three know a lot about fitness. After hearing them three about what they told me and recommended exercises for me I managed to create a routine that I later on divided in two: Upper and lower body are worked on different days (Foolish me, trying to do all at once). It wasn't a light chat, though. I really got into deep conversations on the matter with each one of them three.

I am not fat, but I was pretty skinny. My intention is simply to get fit, to be healthy. I noticed a considerable increase on the size of my back. Abs got harder than before - That's good. Legs are doing fine as far as I know. Pecs are the one part that I haven't seen much improvement, maybe it takes longer but I started focusing more times on them because of this. I've always eat a lot of food (Junk and healthy alike) but always been very skinny. I'm trying to eat a bit more on the junk side so I can become a bit fatter and gain some mass, and then turn it into muscular mass, I'm also trying to eat more meat and drink milk more often than not because of proteins, so I can help my body to develop better.

I just started this in november. Truth is I've been trying to do this all 2013, but never managed to do so because I quickly gave up each time. My advice for people who wants to get fit, from personal experience, is that it's OK if you give up on it; don't push yourself nor pretend that one day you'll wake up and suddenly you will love doing exercise. That was my mistake. You have to feel comfortable with it. Keep trying until you finally take it seriously for real. Maybe not this week. Maybe not this month, hell maybe not even this year, but try to get something you can do different exercises with in your house (Like a pair of 5 Kg. dumbells, as in my case) and every time you see it, remember that getting fitter only depends on you. The motivational stuff you see on the internet won't mean a thing unless you actually started.

I don't go to the gym because there isn't any very close to where I live and I know that if I went to a gym I'd be too lazy to go there, and I wouldn't go on hot days, cold days, rainy days, etc. On your own home, there's nothing to stop you other than yourself. I think people sees it the other way around though, but this is how it works in my case since I don't like going out that much.

Just my personal experience folks. Hope someone reads this and maybe eventually decides to start or something. 

Side note: My personal motivational-boost for getting fit is every time I see a picture of someone around my age (16) on facebook or twitter where they show their body. The kind of guy that does that is also the typical dudebro whose main purpose in life is to drink alcohol, party hard and get laid (Or kiss a lot of girls otherwise). I've met and seen lots of these guys. Never got along with any, mostly because they think they're the alpha males... But I deeply disagree on that. I'd hate seeing my girl friends with these idiots, I'd rather like it to be the one who has their attention myself, even if I wouldn't touch them... First. You know, the value of friendship and such.

TL;DR: I'm getting fit. Also haven't fapped since January 2nd.

4 touch downs in a single game.

Impressive, I lost 40 since October.

5'11 and 165 now. But I still feel chubby at heart.

I cycled 2000km through Germany in 14 days. On a trekking bike with 20kg baggage and alone.
Was quite fun.