CSI: CRIME SCENE INVESTIGATION
CBS, 9:00 p.m. ET
SERIES FINALE: While other series are just starting out tonight, optimistically presenting their very first episodes, the flagship CSI series is saying goodbye tonight, after 15 seasons and more than 300 installments behind them. Original stars William Petersen and Marg Helgenberger are back for this two-hour finale – as is recurring guest star Melinda Clarke as the unforgettable Lady Heather.