This seems like a pretty neat site.
It’s basically a programming practice site. You choose what language you want to learn/improve. They give you exercises to practice.
But this site also has mentors that can give you feedback on your solutions. So, you’re not just submitting solutions that work, but you’re getting feedback on how good your solution from folks who already know the language well.
I’ve decided I’m just going to learn as many new languages as I can. I’m doing new exercises during my lunch hour now.
Also, it’s free. Which is awesome.