 This is an investigational study. Lenalidomide is FDA approved and commercially available. Lenalidomide is approved for the treatment of patients with transfusion-dependent anemia due to Low- or Intermediate-1-risk myelodysplastic syndromes associated with the chromosome 5 abnormality with or without other chromosome abnormalities. Lenalidomide is also approved in combination with dexamethasone for the treatment of patients with multiple myeloma that have received at least one prior therapy. Its use in this study, for relapsed mantle cell lymphoma or large B-cell Non-Hodgkins lymphoma, is investigational. It is currently being tested in a variety of cancer conditions. In this case it is considered experimental. 