I'm 20 years old and pretty soon to be 21, but I spent more time than I'd like to admit on the Internet as a kid (I think you can gleam my experiences in school from that...). What I miss is you could actually 'surf' the Web. Nowadays it's the same 3 or 4 sites, but even 10 years ago, not too far into the past, there was so much to see.
The Internet and old Web 1.0 sites were what made me fall in love with linguistics and languages, a field I still really love today and plan on pursuing in my Master's if the Lord sees fit. I know what I want to do, I have something I'm truly passionate about, and it's thanks in no small part to the Web.
A guide to writing systems and languages, with useful phrases, tips on learning languages, multilingual texts, and much more.
www.omniglot.com
I loved this site as a kid. I still go on it because it really is a beautiful resource for languages. You could spend hours like I did looking at writing systems, obscure languages, and all sorts of stuff like that. There's a few more sites but that's the main one for me.