Deviations of the CMB spectrum from a black-body are a powerful probe of the three-point function of curvature perturbations. Dissipation of acoustic waves in the photon-electron-baryon fluid heats the plasma: the heating is not balanced by an appropriate change in photon number, and a Bose-Einstein spectrum is formed. A non-zero three-point function of curvature perturbations makes the heating rate spatially dependent, so that the observed chemical potential in the sky will be anisotropic and correlated with large-scale temperature fluctuations. In this talk I discuss how the angular correlation of temperature anisotropies and spectral distortions is insensitive to contamination from late-time projection effects (unlike other observables like the CMB temperature bispectrum), making it an excellent, albeit futuristic, probe of primordial non-Gaussianity.