Increase in visible order can be associated with an increase in microscopic disorder. This phenomenon leads to many counter-intuitive phenomena such as entropy driven crystallization and phase separation. I devote special attention to the entropic interaction as a means to tune the range of attraction between colloids. The range of the intermolecular potential determines whether or not stable liquid-vapor coexistence is possible. For short range attraction, the liquid-vapor transition may be located below the sublimation line. Under those conditions, meta-stable critical fluctuations may enhance the rate of crystal nucleation.