  Models with large extra dimensions as well as unparticle models could give
rise to new phenomena at collider experiments due to real emission or virtual
exchange of gravitons or unparticles. In this paper we present the common
implementation of these processes in the Monte Carlo generator Pythia8, using
relations between the parameters of the two models. The program offers several
options related to the treatment of the UV region of the effective theories,
including the possibility of using a form factor for the running gravitational
coupling. Characteristic results obtained with Pythia8 have been used to
validate the implementations as well as to illustrate the key features and
effects of the model parameters. The results presented in this paper are
focused on mono-jet, di-photon and di-lepton final states at the LHC.
