I made it through Stripe's CTF. Here, CTF is a game where you move to levels by exploiting security holes in software built for the game.
I had a lot of fun working through the levels and I learned a lot about web security exploits in practice. I think Stripe did a really good job designing the levels (especially some of the later ones), and hosting the event.
Don't worry, I'm not a l33t hacker, I needed lots of hints to move through the game. However, I think the "cheating" was worth it to learn what the exploits were and to try my hand at implementing them. One of the things I found was that even when you know the exploit, implementing it can still be tricky. Especially since you are typically running exploit code in an environment that you have limited information and/or control over.