There are many coding challenge websites on the Internet today. below are a few of them. the tilde.team shell is a great place to work on solutions to the challenges.
Please, just be mindful of efficient coding practices while working on these.
These challenges focus primarily on practicing various computer security principles
If you know of other internships, opportunities, or other (good) code challenge sites, submit a pull request for this page, or mention it to an admin on IRC.