  We present mid-infrared spectra of the nearby, Ultraluminous Infrared Galaxy
NGC 6240 taken with the IRS on Spitzer. The spectrum of NGC 6240 is dominated
by strong fine-structure lines, rotational H2 lines, and PAH emission features.
The H2 line fluxes suggest molecular gas at a variety of temperatures. A simple
two-temperature fit to the S(0) through S(7) lines implies a mass of 6.7E6
solar masses at T=957K and 1.6E9 solar masses at T=164K, or about 15% of the
total molecular gas mass in this system. Noteably, we have detected the [NeV]
14.3 micron emission line, with a flux of 5E-14 erg/cm^2/s, providing the first
direct detection of the buried AGN in the mid-infrared. Modelling of the total
SED from near to far-infrared wavelengths requires the presence of a hot dust
(T=700K) component, which we also associate with the buried AGN. The small
[NeV]/[NeII] and [NeV]/IR flux ratios, the relative fraction of hot dust
emission, as well as the large 6.2 micron PAH EQW, are all consistent with an
apparent AGN contribution of only 3-5% to the bolometric luminosity. However,
correcting the measured [NeV] flux by the extinction implied by the silicate
optical depth and our SED fitting, suggests an intrinsic fractional AGN
contribution to the bolometric luminosity of about 20-24% in NGC 6240, which
lies within the range implied by fits to the hard X-ray spectrum.
