  A nodal Enriques surface can have at most 8 nodes. We give an explicit
description of Enriques surfaces with 8 nodes, showing that they are quotients
of products of elliptic curves by a group isomorphic to $\Z_2^2$ or to $\Z_2^3$
acting freely in codimension 1. We use this result to show that if $S$ is a
minimal surface of general type with $p_g=0$ such that the image of the
bicanonical map is birational to an Enriques surface then $K^2_S=3$ and the
bicanonical map is a morphism of degree 2.
