diff --git a/Related-Projects.md b/Related-Projects.md
index c4e40e1..a6fddda 100644
--- a/Related-Projects.md
+++ b/Related-Projects.md
@@ -28,6 +28,7 @@
 * [mruby-pack](https://github.com/iij/mruby-pack) Array#pack implementation by [iij](https://github.com/iij)
 * [mruby-mtest](https://github.com/iij/mruby-mtest) Minimum Test Framework by [iij](https://github.com/iij)
 * [mruby-iconv](https://github.com/mattn/mruby-iconv) libiconv interface by [mattn](https://github.com/mattn)
+* [mruby-sleep](https://github.com/matsumoto-r/mruby-sleep) sleep binding by [matsumoto_r](https://github.com/matsumoto-r)
 
 ## Web Interfaces
 
@@ -54,4 +55,4 @@
 
 ## Hacks
 
-* [Watching bidet toilet seat, and tweet](http://eleclog.quitsq.com/2013/01/toilet-tweet-bot.html) (in japanese)
+* [Watching bidet toilet seat, and tweet](http://eleclog.quitsq.com/2013/01/toilet-tweet-bot.html) (in japanese)
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