Schiminovich and I re-tooled our GALEX–USNO project (build an all-sky quasar catalog, using the SDSS as a training set) into a GALEX–2MASS project. It appears that the 2MASS photometry is better suited to our purposes, although the 2MASS source density is not as high.
Schiminovich, Wu, and I looked at the pixel level at Spitzer IRS spectra. There are some very strange things in the statistical properties of the sky frames that we don't understand. But it appears that we may be able to do science without fully understanding this.