We consider the pentagram map on the space of plane convex pentagons
obtained by drawing a pentagon's diagonals, recovering unpublished
results of Conway and proving new ones. We generalize this to a
"pentagram map'' on convex polygons of more than five sides, showing
that iterated images of any initial polygon converge exponentially
fast to a point. We conjecture that the asymptotic behavior of this
convergence is the same as under a projective transformation.
Finally, we show a connection between the pentagram map and a certain
flow defined on parametrized curves.