Microsoft announced today that the beta for Project Spark, their new game creation tool, is now available on the Xbox One. The tool had previously only been available to users with a Windows 8.1 PC. If you were in the PC beta you automatically have access to the Xbox One version and any content created on the PC version will now be available for development and playing on the Xbox One.
If you aren't in the beta already you can sign-up at the Project Spark website. Microsoft has been pretty good about getting people into the beta pretty quickly and I would expect that Microsoft will be approving a lot more people now that the beta has been opened up on the Xbox One. Be sure to follow them on twitter for more chances to get into the beta as well as the chance to get more tips and tricks about how to use the tools in the game.
If you want some inspiration or idea of what you can do in the game check out this montage of footage from things that people have already built with Project Spark (including yet another Flappy Bird clone)