In this phase I/II study,investigators are evaluating the feasibility and efficacy of the combination of BKM120, an oral inhibitor of PI3 kinase, and bevacizumab in the treatment of patients with relapsed/refractory GBM. In the Phase I part of the trial, the optimal BKM120 dose to be administered with a standard dose of bevacizumab will be determined in patients with refractory solid tumors. Although it is unlikely that the concurrent administration of bevacizumab will alter the pharmacokinetics of BKM120, limited pharmacokinetic sampling will be performed on all patients treated during the Phase II portion of the study. Assuming this combination is feasible, the Phase II portion of the study will proceed, using the doses determined in the Phase I portion. In the phase II portion, eligible patients will be limited to those with recurrent/progressive GBM following 1st line combined modality therapy.