Abstract: There are 2 combinatorial structures intimately connected
with the classification of conformal field theories. I'll give their
simple definition, review what's known, and state some (possibly
disturbing) curiousities. The classification of CFTs is interesting
for its own sake, and also because of the remarkable variety of its
points-of-contact with other areas of math (A-D-E, Fermat, subfactors,
vertex operator algebras,...).