This library is called gtk_paradise, the successor to the older gtk_module project. It extends the Gtk/Gdk part of ruby-gtk2 / ruby-gtk3, including some add-on colours - see the online-documentation for more information in this regard. The idea behind this gem is to make the ruby-gnome bindings more "ruby-like" rather than have them a 1:1 mapping to the C source code. Some custom widgets are also created, to make working with the ruby-gtk bindings easier. Remember that this is very beta-ish software! Do not expect it to become too stable shortly; I am still experimenting and as a result, changing a lot. Last but not least, for some strange reason this project was quite popular (in regards to active downloads per release), at the least when it was called gtk_module. I am not entirely sure why that was so, because the project really only makes sense after you already know ruby-gtk itself (so check ruby-gtk out before you give this project here a try), but perhaps there may be several ruby users interested in GUIs + ruby, such as gtk in general. This means that I will attempt to improve the quality of this project over time, but it is nonetheless merely a hobby project, and it is not one of my more important projects either. Thus, you should not expect too much from this project. It has been primarily added to cover my use cases in regards to ruby-gtk, and it still (!) heavily focuses on gtk2 rather than gtk3 (even though gtk3 looks much cleaner than gtk2; I just did not have enough time to port all old ruby-gtk2 code to ruby-gtk3 yet).