Patients receive vorinostat orally (PO) once daily (QD) on days -7 to -1 (course 1 only) and days 8-14 and 22-28 and temozolomide PO QD on days 1-5. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity. Patients previously treated with standard radiotherapy and temozolomide receive maintenance temozolomide PO on days 1-5.