You said any 'version' of OpenGL...does that make OpenGL ES2 an option? If so I would recommend WebGL. Not as full featured as OpenGL but it has been a good learning tool to get me started. Easy to show off your work too since it'll run in most browsers (only exception is IE and Android browsers are hit/miss). I've been able to use Google Drive for hosting which is free (although you have to jump through a few hoops to make it work). All you need for WebGL is coding knowledge of Javascript/GLSLES/OPENGLES API calls and a bare minimum of HTML5.
This guy did a really good tutorial job...
http://learningwebgl.com/blog/?page_id=1217
Good book and some JS libraries to get you started. His library handles most of the matrix stuff for you...
https://sites.google.com/site/webglbook/
Good luck.