  We show that there exist flat surface bundles with closed leaves having
non-trivial normal bundles. This leads us to compute the Abelianisation of
surface diffeomorphism groups with marked points. We also extend a formula of
Tsuboi that expresses the Euler class of a flat circle bundle in terms of the
Calabi invariant of certain Hamiltonian diffeomorphisms to surfaces of higher
genus and derive a similar formula for the first MMM-class of surface bundles
with punctured fibre.
