Mos Def, fashionably late with rap that's great

The rapper-turned-actor Mos Def has done his most engaging work in front of a camera and not a microphone in recent years. From his canny impersonation of Chuck Berry in the Chess Records biopic

Cadillac Records

to a guest shot on last season's

House

and a string of bit parts on

Chappelle's Show

, he has proved himself a versatile and inspired performer, but his rhyming skills ossified as his acting career blossomed.

That changed this spring with the release of his fourth solo album, The Ecstatic. Sampling sources as diverse as Philly soul and Turkish pop, the album pulses with an energy not seen in the decade since Black on Both Sides, his first album after splitting from his Black Star partner Talib Kweli.

That same energy was in evidence at the Electric Factory on Thursday, although not all of the audience stuck around to find it out. Mos didn't take the stage until well after midnight, an hour after his scheduled set time and almost four hours after the show's 8:30 start. For an artist who has devoted his career to pushing the boundaries of rap, the night did little to dispel hip-hop's reputation for sprawling, undisciplined live shows.

Luckily, Philadelphia's Black Landlord kicked things off with a jolt that kept the crowd energized through lackluster sets by Medina Green and Whosane. A nine-piece band led by former Goats frontman Maxx Stoyanoff-Williams, their music mixed funk, soul and rock with Maxx's old-school delivery. Rather than standard-issue braggadocio, their raucous, infectious songs offered shout-outs to the older generation ("Grandmoms") and cold-turkey psychodrama ("Mind Over Matter").

A rambling but intriguing set by New Orleans rapper Jay Electronica, who pulled Floetry's Marsha Ambrosius from the wings for an impromptu freestyle, was followed by a blistering Kweli, who held the stage for most of an hour - and then, by 45 minutes of dead air.

When Mos finally appeared, the audience had already begun to trickle out, and most of them were gone by 2 a.m., when he started to wrap things up. But those who stayed were treated to a wide-ranging demonstration of his prodigious talents. On his own and with Kweli, who returned for a Black Star mini-reunion, Mos ran the gamut from higher-consciousness spiels to diss-oriented ballads, occasionally accompanying himself on the drum kit set up to one side of the stage. He kept going even after the show was over, drumming along with the songs on the P.A. It might have taken him a while to show up, but once he did, he was there to stay.