College students know Kal Penn from movies and TV shows - as Kumar or Lawrence Kutner.

But Penn was at Pugh Hall on Saturday to talk to UF students about Sen. Barack Obama, the presumptive Democratic nominee for president.

Penn, who stars in the "Harold & Kumar" films and plays Dr. Lawrence Kutner on the show "House M.D.," wasn't there to act or be funny, but he made most of the 300 students filling the room laugh anyway.

UF is one of the stops on his Florida college tour to endorse Obama. His scheduled visits for the weekend included the University of Central Florida, the University of Miami, Florida International University and Florida State University.

He said he's always been a registered Independent and was never active in politics until he heard of Obama. A more personal situation made him care, too.

Penn said while he lived in Texas, he had a friend working a minimum-wage job to save up for college. His friend got an offer from a corporation to drive a truck for a year in Iraq - for $90,000.

Penn's friend asked him for advice.

"It was really sad that the richest country in the world could only offer our buddy two options," Penn said.

His friend didn't take the offer, but the proposition left Penn more cynical about politics and a possibility of something better.

He said his political mindset started to change when he watched Obama give the keynote speech at the 2004 Democratic National Convention.

"And there's this skinny guy with big ears talking about no red states and no blue states, but a United States," Penn said.

"By the end of the speech, I thought, 'Wow, this guy really needs to run for president.'"

He said he was also impressed with Obama's integrity when he turned down corporate law firms to work in civil rights law and that he taught constitutional law.

When Obama did, Penn signed up as a campaign volunteer in 2007.

In an interview before the event, he said he likes Obama's understanding that solving the environmental crisis is directly related to boosting the economy.

Specifically, he approves of Obama's plan to reduce carbon emissions by 2050 and create 5 million "green" jobs.

He added that he was proud of Obama's choice for running mate, Joe Biden.

Penn told the crowd that with 900,000 college students in Florida, they are a group that can change the face of the presidential election. He said 400,000 votes decided the Florida vote in 2004, and there is no doubt about the voting power of college students.

He urged students to vote, get their friends to vote and volunteer for Obama's campaign for people like his friend in Texas.

It was enough to convince UF freshman Bianca Orfanos, who walked in as an undecided Independent, to vote for Obama.

"Yes, definitely," Orfanos said with her friend in an "Obama yo mama" T-shirt cheering next to her.

"I think that was kind of the swaying factor for me."

VIDEO: Kal Penn's speaks at UF.