In this talk I will present numerical simulations of dynamically relaxed rotating dense stellar systems (e.g. Globular, Nuclear Star Clusters). Targeted are systems characterized by their long-term evolution (Gyr) and particularly, by the presence of initial axi-symmetry due to rotation. A central massive Black Hole is alternatively included, which grows due to consumption of stellar matter. Our models are compared to available observations of galactic rotating globular clusters, and is concluded that initial rotation significantly modifies the shape and lifetime of these systems. Recent simulations of clumped Dark Matter particles can reproduce the Galactic rotation curve over a Hubble time. The advantages of up-to-date high performance computing is discussed in this context.