We provide exact solutions to the Einstein equations when the Universe contains vacuum energy plus a uniform arrangements of magnetic fields, strings, or domain walls. Such a universe has planar symmetry, i. e., it is homogeneous but, not isotropic. Further exact solutions are obtained when dust is included and approximate solutions are found for $w\not=0$ matter. These cosmologies also have planar symmetry. These results may eventually be used to explain some features in the WMAP data. The magnetic field case is the easiest to motivate and has the highest possibility of yielding reliable constraints on observational cosmology.

42 pages, 24 figures, 3 tables