I am going into junior year and I have interest in computer science and web development. How I could I turn this interest into an extracurricular and do something meaningful with it which would in turn help my college application for highly selective schools?
Make stuff! Build websites or other programs and put them up on GitHub. Offer your website building services to clubs and programs at your school. If you are in another extracurricular that would benefit from having a website, build a website for that club. If your school has a computer science club, join it. If not, start one. Related clubs would include robotics and technology. Depending on your skill set/level, you might be able to get an internship as well.
There are plenty of gaming groups that you can develop their php based face page, or forums for money. Just google different popular games that require a group or community and then contact their lead or admin to offer services. I’ve built loads of different websites for gaming groups already and tons of forums.