OpenEuphoria

GTK has two "event handlers" - one "fires off" every x milliseconds, which you choose when writing the program, the other runs as fast as the processor can go , calling your Eu game function(s) whenever there isn't input from the user or a graphic update to be done.

The second would be a likely candidate for a game. EuGTK also has an openGL "container", but openGL is something that I don't know anything about, so I haven't written any demos for openGL. A wrapper for openGL calls would have to be found, modified, or written.