  We investigate the possibility that the dark matter candidate is from a pure
non-abelian gauge theory of the hidden sector, motivated in large part by its
elegance and simplicity. The dark matter is the lightest bound state made of
the confined gauge fields, the hidden glueball. We point out this simple setup
is capable of providing rich and novel phenomena in the dark sector, especially
in the parameter space of large N. They include self-interacting and warm dark
matter scenarios, Bose-Einstein condensation leading to massive dark stars
possibly millions of times heavier than our sun giving rise to gravitational
lensing effects, and indirect detections through higher dimensional operators
as well as interesting collider signatures.
