Patients receive rituximab intravenously (IV) on day 1 and cladribine IV over 2 hours on days 1-5. Patients then receive temsirolimus IV over 30 minutes on days 1, 8, 15, and 22. Patients also receive filgrastim subcutaneously (SC) on days 6-15 or pegfilgrastim SC on day 6. Treatment repeats every 28 days for up to 6 courses in the absence of disease progression or unacceptable toxicity.