I discuss what we have learned about the nature of interstellar turbulence from the technique of radio wave scintillation. My main interest is in the form of the turbulence, i.e. what physical models and equations are appropriate. Radio scintillation observations show that the density irregularities responsible for radio wave scintillation are elongated and probably magnetic-field aligned and characterized by a Kolmogorov spatial power spectrum. It seems reasonable, and almost unavoidable, that the plasma density fluctuations responsible for these scintillations coexist with and are produced by fluctuations in magnetic field and plasma flow velocity which share these properties of the density fluctuations. The main thesis of this paper is that magnetic field and plasma velocity fluctuations with such properties emerge from approximate statements of magnetohydrodynamics such as reduced magnetohydrodynamics or two dimensional magnetohydrodynamics. It is suggested that much insight regarding interstellar magnetohydrodynamics can be gained from study of these relatively simple and intellectually accessible equations.