For the inital quantum gas experiments the coherence properties and quantum degeneracy of the
ensembles set the newly created states of matter dramatically apart from classical gases. Not soon
after, however, the internal degree of freedom of the particles was made available as a free
variable and led to even richer quantum manybody systems.
Analog to this, initial experiments with degenerate gases in optical lattices were focusing on the
external degrees of freedom - conduction vs. insulators in the lowest band, dynamics and band
fillings. In the last few years, however, andvances in the preparation and manipulation of such
gases have made it possible to consider optical lattice systems as quantum simulators for systems
with more degrees of freedom such as including more than one band, or considering ground states
involving correlations of external and internal states, such as a particle's (real or effective)
spin. I will discuss current experimental advances to implement spin and multi-band physics and
discuss how different approaches from the ones implemented with Alkali atoms are possible with less
common types of atoms with different internal structure, such as in our new project employing
ensembles of alkaline-earth-type atoms in optical lattices.