  We expose some applications of the finite gap integration method which
involve singular spectral curves. They include orthogonal curvilinear
coordinate systems corresponding to spectral curves with geometrical genus
zero, finite gap Frobenius manifolds, and soliton deformations of spectral
curves corresponding to equations with self-consistent sources. This is an
extended version of the talk given at the conference "Geometry, Dynamics,
Integrable Systems --- GDIS 2010" (Serbia, September 7--13, 2010).
