Best Bets on TV Tonight

"CSI: Crime Scene Investigation" (9 p.m., CBS): Danger apparently gets a little too close for comfort with one of the members of the forensics team on "CSI: Crime Scene Investigation." A man Catherine flirted with at a bar suddenly reappears in her life as the suspect in a murder investigation.
"The O.C." (9 p.m., Fox): With graduation just weeks away on "The O.C.," the focus turns to college as Ryan, Seth, Summer and Marissa head out on their respective pre-frosh orientations. And while visiting Brown, Seth runs into an old friend.
"Smallville" (8 p.m., The WB): A masked man takes Lex away and threatens a snoopy Martha.