The beauty of classic punk rock lies in its utter simplicity: Crude rhythms, rude attitude, pumping adrenaline and a loudly pronounced point of view are key. Once you get sucked in by that formula, any punk band sounds good at first because the musical rush is so basic, familiar and overwhelming. That's also the reason most punk bands and records ultimately turn out to be crap. In punk the good stuff actually unfolds and gains meaning as you listen without sacrificing any of its electric, haywire immediacy. And Green Day are as good as this stuff gets.

With its members barely into their 20s, this Bay Area trio brought punk kicking and sneering onto the pop charts with its third album, last year's Dookie. The mere fact that Insomniac isn't a "long-awaited follow-up" points to how smart these guys really are. Spending a lot of time recording and slaving over their mosh-pit ditties would've been a surefire recipe for disaster. Insomniac wastes no time offering up the same kind of pure pleasures that enlivened Dookie: ramalama hooks, goony humor and punk commitment and passion. Once again, guitarist and singer Billie Joe's adenoidal vocal whine is expertly deployed; he remains engaging rather than annoying just barely, but that's part of the charm. And without slipping into virtuosity, Billie Joe, bassist Mike Dirnt and drummer Tre Cool have improved and tightened up their playing; they give Insomniac's short, fast songs leaping, dynamic arrangements, and they vary the rhythmic pace of their all-out assault just enough to keep things interesting.

Insomniac begins at a breathless pogopop pace with "Armatage Shanks" and "Brat." When a lyric fragment jumps out of the thick mix, it sticks like glue after the sonic rumble moves on: "Stranded ... lost inside myself" on "Armatage" or "I'm getting bored, and I'm going nowhere fast" on "Brat" are typical. They may read like clichs on paper, but with the music propelling them, Billie Joe's puns and comic protests ring with truth if not profundity.

Not every Green Day chant is so happy-go-lucky, however. The circular choruses of "Stuck With Me" and "Geek Stink Breath" turn in on themselves, summoning up a believable nihilistic fury. "I'm blowing off steam with methamphetamine," Billie Joe barks on the latter, "and my pulse is beating out of time." While he sweats and shakes, the band duplicates the off-center nervous energy of a speed trip. But Green Day may be better at uplift than down-in-the-gutter wallowing. Major chords and martial rhythms turn "No Pride," "Bab's Uvula Who" and "86" into stirring, Clash-style anthems even though the lyrics deal with alienation ("No Pride"), all-consuming anger ("Bab's") and the easy comforts of nostalgia ("86").

For self-declared "snot noses with no jobs," Green Day actually possess a subtle sense of humor. Witness "Brain Stew" on Insomniac: It's a slogging Ozzy-style metal meltdown that provides a breather and some comic relief without lapsing into cheap irony or sarcasm. And it, er, rocks. Proof that the once-rigid dividing line between punk and metal rock's traditional homes for troubled teens has been erased over the last few years.