What might have been Penn State's best concert of the year was a free one.

Mos Def lit up Rec Hall last night, sending the audience into frantic fury while orating an onslaught of lyrics. Microphone kissed, Mos controlled the crowd with his arm while controlling the tempo with his feet. Joining him for the second half of his set was his band, the Black Jack Johnson Project.

But before any instruments were picked up, Mos gave one warning.

"This ain't rap-rock. This is ghetto rock," Mos said to the crowd. "It's a whole lot of hip-hop and a whole lot of rock n' roll."

Smirking throughout his playful hits "Ms. Fat Booty" and "Hip-Hop", Mos turned to stern passion.

"We must have harmony. We must have unity. We must have peace," Mos prayed as he called for togetherness in songs such as "War" and "Ghetto."

Psychedelic feedback screamed almost as loud as Mos near the end of the latter two songs, rewarding him with resounding applause throughout Rec Hall.

Solos around the stage hinted at blues, funk and soul during the extended remix of "Rock n' Roll." Instead of jamming to the punk rock ending as on his album, Mos played with the tempo, turning the joint out into a reggae and blues jam.

In between songs, Mos sneaked in a poem reflecting upon the chaos in New York and Afghanistan. But his most triumphant moment was his powerful slam of the recording industry in his new song, "The Rapeover", a rendition of Jay-Z's, "Takeover."

As close to Mos as possible, Lucila Betharte (freshman-chemical engineering) flailed her body in all directions below the stage, feeling Mos' flow. The only thing keeping her from bouncing onto the stage was a wall of four-foot-high speakers.

"He has a lot of positive energy and is very poetic," Betharte said. "He's more deep than most artists out there."

Behind her were about 2,000 fans, bouncing in unison as if they were all on the same trampoline. Hips churned with the deep bass roll, heads bobbed with each cymbal smack and eyes squinted with each wail on the "gee-tair."

"I thought it was hot," said Jason Merriweather (senior-management). "The band was unexpected but I liked it."

After his soulful tribute to his mother, "Umi Says", Mos' closed the show, fatigued from his release of energy on stage.

"I've been on the road for a while now," Mos said. "I want to go home and do some laundry."