  Time-dependent solutions of supergravity and string theory are studied. The
examples are obtained from de Sitter deformation of gauge/gravity dualities,
analytical continuation of static solutions, and ``exactly solvable''
worldsheet models. Among other things, it is shown that turning on a Hubble
parameter in the background of a confining gauge theory in four dimensions can
restore chiral symmetry. Some of the solutions obtained from analytical
continuation have the interpretation of a universe with a bounce separating a
big bang from a big crunch singularity. In the worldsheet context, it is argued
why string propagation close to a Milne-type cosmological singularity might be
physically non-singular.
