There are already many Crystal programs in GitHub. And made a eco-system.

Crystal semantic is similar to Ruby,so translation from Ruby eco-system to Crystal eco-system is easier than other languages.

#Libraries and Applications already developped

Crystalshards show GitHub Projects [Crystalshards] (https://crystalshards.herokuapp.com/)

If you follow Ｔｗｉｔｔｅｒ,you can receive the update status of Crystalshards https://twitter.com/shardscrystal

Crystalshards is of cource written by Crystal. https://github.com/zamith/crystalshards

Twitter update status of Crystalshards is of cource written by Crystal. https://github.com/Vikaton/crystalshards-twitter

#Awesome!

Awesome Crystal: A curated list of awesome Crystal code and resources. Inspired by awesome-awesomeness. http://veelenga.github.io/awesome-crystal/

A collection of awesome Crystal libraries, tools, frameworks and software https://github.com/rilut/awesome-crystal

crystal deps Package Manager https://github.com/manastech/crystal/wiki/crystal-deps-Package-Manager

crenv: Crystal version manager. https://github.com/pine613/crenv

crystalbrew: Crystal version manager. https://github.com/pine613/crystalbrew

[Trending repositories: Find what repositories the GitHub community is most excited about today.] (https://github.com/trending?l=crystal)

#Sample programs

[Examples for Crystal Language] (https://github.com/KamilLelonek/crystal-examples) (http://www.slideshare.net/squixy/crystal-45694037)

[Introduction-To-Algorithms-Crystal] (https://github.com/Vikaton/Introduction-To-Algorithms-Crystal)

[Solving Project Euler with Crystal] (https://github.com/jtomschroeder/ProjectEulerCrystal)

[Some poorly done solutions for google code jam problems] (https://github.com/ssvb/ssvb-in-google-code-jam) (https://code.google.com/codejam)

[An example toy robot simulation written in crystal] (https://github.com/lokulin/toy-robot-crystal#toy-robot)

[A collection of containers & algorithms for the crystal programming language] (https://github.com/jtomschroeder/crystalline)

[mal - Make a Lisp forked by rhysd] (https://github.com/rhysd/mal/tree/master)

[mal - Make a Lisp forked by asteryte] (https://github.com/asterite/mal)

[ Matz "すげーっ”　：　ezoe command written in Crystal ] (https://github.com/rhysd/ezoe)

[An example Ruby extension written in Crystal] (https://gist.github.com/notozeki/7159a9d9ab9707a22129)

reddit Crystal for those that only know Ruby

#Benchmarks

[Some benchmarks of different languages] (https://github.com/kostya/benchmarks)

[Crystal implementations for The Computer Language Benchmarks Game] (https://github.com/kostya/crystal-benchmarks-game)

[LPATHBench] (https://github.com/logicchains/LPATHBench)

[mal - Make a Lisp] (https://github.com/kanaka/mal)

[Perlin noise benchmark] (https://github.com/nsf/pnoise)

[Redis Benchmarks] (https://github.com/stefanwille/redis-client-benchmarks)

[ REDIS Benchmarks Result: Crystal vs Ruby vs C vs Go vs ... ] (https://www.stefanwille.com/2015/05/redis-clients-crystal-vs-ruby-vs-c-vs-go/)

[席替えスクリプト2015! ] (https://github.com/pepabo/sekigae2015)

[awesome-ezoe] (https://github.com/mattn/awesome-ezoe)

#A web service that runs your Crystal code and displays the result. Compile & run code in
http://carc.in

Code is here

Try it online!

[play.crystal-lang.org] (http://play.crystal-lang.org/#/cr)