adamOS is a free to use OS that I am making thanks to Cosmos (https://github.com/CosmosOS/Cosmos)
Currently, you cant really do anything yet, but one day, you will be able to have all kinds of fun! Such as:
-Installing it!
-Running commands!
-Making and edititng text documents
-Using a GUI, for those that want one
-Playing games
-Whatever comes to mind :D
This is just a fun little side project, but, if you happen to come across this and wanna contribute/check it out, please feel welcome to!