A pulsed molecular beam cavity Fourier transform microwave spectrometer was used to measure pure rotational spectra of nine isotopomers of Ne-2-N2O, and of three isotopomers of the Ar-2-N2O van der Waals trimer. For Ne-2-N2O, these are (NeNe)-Ne-20-Ne-20-(NNO)-N-14-N-14-O-16, (NeNe)-Ne-20-Ne-22-(NNO)-N-14-N-14-O-16, (NeNe)-Ne-22-Ne-22-(NNO)-N-14-N-14-O-16, (NeNe)-Ne-20-Ne-20-(NNO)-N-15-N-14-O-16, (NeNe)-Ne-20-Ne-22-(NNO)-N-15-N-14-O-16, (NeNe)-Ne-22-Ne-22-(NNO)-N-15-N-14-O-16, (NeNe)-Ne-20-Ne-20-(NNO)-N-14-N-15-O-16, (NeNe)-Ne-20-Ne-22-(NNO)-N-14-N-15-O-16, and (NeNe)-Ne-22-Ne-22-(NNO)-N-14-N-15-O-16. Those for Ar-2-N2O are (ArAr)-Ar-40-Ar-40-(NNO)-N-14-N-14-O-16, (ArAr)-Ar-40-Ar-40-(NNO)-N-15-N-14-O-16, and (ArAr)-Ar-40-Ar-40-(NNO)-N-14-N-15-O-16. The spectra were measured in the frequency range between 3 and 18 GHz. Both a- and c-type transitions were measured for all Ne-2-N2O isotopomers. In the case of the mixed, (NeNe)-Ne-20-Ne-22 containing, isotopomers a small b-dipole moment occurs and two b-type transitions were measured. In the spectra of Ar-2-N2O only b- and c-type transitions were measured. Rotational and centrifugal distortion constants were determined for all the isotopomers of each complex. The spectral analyses show that Ne-2-N2O is a highly asymmetric prolate rotor (kappa=-0.158 for (NeNe)-Ne-20-Ne-20-(NNO)-N-14-N-14-O-16) while Ar-2-N2O is a highly asymmetric oblate rotor (kappa=0.285 for (ArAr)-Ar-40-Ar-40-(NNO)-N-14-N-14-O-16). Both trimers were found to have distorted tetrahedral structures with the rare gases tilted towards the O atom of the N2O subunit. Nuclear quadrupole hyperfine structures due to both terminal and central N-14 nuclei were observed and analyzed to give the nuclear quadrupole coupling constants, chi(aa)(1), chi(bb)(1) and chi(aa)(2), chi(bb)(2). The resulting spectroscopic constants were utilized to derive ground state effective structures, ground state average structures, and partial substitution structures. Harmonic force field analyses were performed for each complex using the obtained quartic centrifugal distortion constants. The results of the spectroscopic analyses are discussed in the light of possible three-body nonadditive interactions.