What do I need to write a small game in ruby?

Hi,

I am very, very new to programming and i started to learn ruby as a
first language from the excellent book 'Learn to program by Chris
Pine'.

Now that I finished the book I would like to study a little bit about
something that does not running in the command pompt, but has an
interface like a game.

Basicly I set out a little project for myself: I would like to display
a 2D sqare on the screen and be able to move it around with the cursor
buttons.

The problem is that i have no idea about where to start as everything
i wrote before was running in the shell.

Do i need to add a GUI framework to the basic ruby installation to be
able to do that like Green Shoes by _Why or do I have to use something
like the GTK2?

Also if you can, could you please recommend some study material on the
subject, preferably books but if you know of any, some simple online
tutorial would be good too.

Thanks in advance for everyone who taken the time to answer this,

Kind Regards,

Loren

As far as I know

http://rubygame.org/

or this http://www.libgosu.org/

http://www.rubyinside.com/video-game-ruby-tutorial-5726.html

http://shoesrb.com/

You could of course use Shoes, Red Shoes, or Green Shoes. Have you seen the Pong game done in Shoes?

http://vgoff.posterous.com/pong-in-purple-shoes shows the ending screen and the flash demo if you click on the pong link there.