I have been enjoying 4clojure, although I found myself hitting a wall a few times, mostly due to not knowing about some function that I needed to solve the problem. It'd be great if there were hints available without looking at a completed solution - eg "try using 'reduce'".

Also, I have enjoyed the Clojure koans as well: https://github.com/functional-koans/clojure-koans

Stop by #4clojure on freenode, the site devs hang out there (myself included) and happily give pointers on problems. Also, the main #clojure channel, while busy, is a great resource -- Clojure has a pretty welcoming community.

A link on the "Solutions" page to the next problem would streamline things some. I followed the top solvers so I could see how far off my solution ended up.

Once you solve a problem you get a link to the solutions, but if you hit "Back" you end up back on the problem anew, with no link to move on.

Takes some tab management to keep the "next problem" link and see the other solutions.

I've never programmed in Clojure or Java before, I figured I'd give it a try. I got hung up on a very early, and with no way to see the solution I'm stuck googling (to no avail) and trying random things (waste of time). Why can we not see the answers? Is this a standardized test or a learning tool? I'd feel silly going to a IRC channel to ask the devs what the answer to intro to strings was.

If you choose to "follow" some of the people who've completed all of the exercises you can then view their solutions. I too found this confusing early on.

I found this very useful http://clojure.org/cheatsheet

Sites like this are the best way to learn any language. Keep up the good work, and I might start learning me some clojure soon enough.

I feel oddly proud of my .1% contribution to this count. 4clojure has been really useful, thanks to everyone who's had a hand in creating it!

I love sites like these! I wish there was one for every language and every learning subject.

Take a look at http://projecteuler.net/problems It's a wonderful collection of non language specific mathematical and/or computer programming problems.

Python challenge is interesting too, but not a good intro to the language.

http://www.pythonchallenge.com/

upon a cursory look I couldn't find a decent version for ruby, but there are many out there that do it differently.

You can see the current count in real-time on the front page of the website. Exciting stuff!

Great website. I started with "The Little Schemer" and SICP, and then also started learning Clojure in parallel with just the cheatsheet and 4cloure.

The site is pretty fast. It states it's hosted by Clojure. I wonder what's the architecture layout is.

Whilst it doesn't tell you about the stack it's running on, the site code is open source: https://github.com/4clojure/4clojure

Looks like mongodb + compojure + some other interesting libraries (clojail for protected eval, for example), running on a Linode.

This is correct. It is worth noting that our setup is hardly complex or clever.