Additional Study Information: The purpose of this study is to learn more about the treatment of children and young adults patient with relapsed (has returned) and progressive medulloblastoma (brain tumor). This study is being done to find out if bevacizumab can be safely given in combination with five study drugs given by mouth, thalidomide, fenofibrate, celecoxib and alternating every three weeks of etoposide and cyclophosphamide. Researchers want to evaluate whether the frequent delivery of low doses of study drugs chemotherapy will work for your cancer, while reducing the toxicity associated with standard dose chemotherapy. The study drugs will be given for 12 months duration based on how well the participants will tolerate the study drugs and the response. Each treatment cycle is 21 days long. The study is composed of the following periods: Screening, Treatment and Follow-up.