Run these test programs without any parameters and they should display on your second monitor. With an optional single argument you can pass the number of the display you want to display on.
mglTestAlignment: Alignment of textures
mglTestDots: Draws dots
mglTestGamma:
GUI controlled gamma
mglTestLUTAnimation: Gamma LUT animation
mglTestStencil: Demonstrates stencil functions
mglTestTex: Draws a gabor
mglTestTexMulti: Draws many small images to screen
mglTestText: Draws text
mglTestKeys: Returns keyboard codes