Re: Silly question...
@frank ly
Within General Relativity, gravity is not really a force in the same way as, say, the electro-magnetic force - it is more a result of the curvature of spacetime by massive bodies.
Essentially, the Newtonian idea of the 'force' of gravity is (under Einstein) simply a manifestation of the curvature of spacetime, as influenced by mass or, more precisely, the 'stress-energy tensor', which is effectively a combination of mass, energy and momentum.
In other words, the curvature of spacetime that results in the apparent 'bending' of light is gravity.
Of course, Neutrinos are affected by gravity too! (And would be even if they were massless.)