II. Estimate the rates of objective response observed prior to disease progression during the first four courses of treatment with bevacizumab and irinotecan hydrochloride in patients with recurrent or progressive medulloblastoma (Stratum C [closed to accrual as of 10/27/2009]) or recurrent or progressive ependymoma (Stratum D [closed to accrual as of 7/29/2010]).