2D Lorentzian Gravity as 2D Euclidean Gravity with Ising Spins
  We suggest a generalization of the dynamical triangulation approach to quantum gravity with both timelike and spacelike edges, which can serve as a toy model for quantum gravity in the Lorentz sector in two dimensions. It is possible to consider the model in a purely Lorentzian sector or to relax this constraint and allow local signature changing moves. We show that, with suitable conventions, the model is equivalent to an Ising model coupled to 2D Euclidean quantum gravity and conduct a preliminary numerical simulation of the Lorentz sector. 
W. Beirl and D.A. Johnston