There are some nice little games and demo applications for your entertainment. Most of the demos are targeted to developers who are interested in learning from the code, which is of course open source as is everything Haiku.

BSnow	Let it snow.
Chart	Moving through stars and galaxies.
Clock	An analog clock.
Cortex	See the media_server in action.
FontDemo	A slideshow through all your fonts.
GLDirectMode	A demonstration of OpenGL.
GLTeapot	The rotating OpenGL rendered teapot.
Gradients	A demonstration of the gradient API .
Mandelbrot	Computing fractals.
Pairs	A game to find pairs of matching icons.
Playground	Test the drawing API .
Pulse	See your CPU's workload.
Sudoku	This century's "Solitair".