Say that I have a representation VV_\ell of SO(3)\rm SO(3) , with angular momentum number \ell . In Dirac notation, states in VV_\ell can be represented in the form v=m=cm,m,|v⟩ = \sum_{m=-\ell}^\ell c_m |\ell,m⟩, where, if the representation is real-valued, we require cm=(1)mcmc_{-m} = (-1)^m c_m^* . I would like to randomly sample from this space , i.e., the vector v|v⟩ and/or its coefficients cmc_m , in a way which is invariant under the action of SO(3)\rm SO(3) on this representation. I'm hoping this is a standard result -- I'm grateful for any pointers, or, more generally, for explicit answer =).