* Something For Nothing (Charlie's, 362 California St . , Ventura, 648-6688) Rumor has it that SFN's alter ego, the dreaded Knight Diamond, will rear its four shaggy heads tonight. Just messing around, these four guys, no matter who they think they are, are better than 90% of those bands on MTV trying to be loud and obnoxious.
* Tom Ball & Kenny Sultan (The Grill, 1279 Coast Village Road, Montecito, 969-5969) Good-time acoustic blues brilliantly performed by these Santa Barbara veterans.
* Leo Downey Band (The Ketch, 514 State St . , Santa Barbara, 564-3231) These guys play tight, original rock and Leo has enough girls giving him the eye to qualify as a Santa Barbara version of Tom Cruise.
* Lion I's (Charlie's) It's always a serious dance party when these reggae rockers play anywhere in the Western Hemisphere.
* Leo Downey Band (Fess Parker's Red Lion Resort, 630 E. Cabrillo Blvd . , Santa Barbara, 564-4333) Gee, I wonder if Fess'll come out and sing one of his Davy Crockett songs? Probably not. Leo returns Saturday night.
* Raging Arb and the Redheads (Hussings Cantina, 3695 Harbor Blvd. Ventura 656-0669) The ultimate dance party in Ventura. Just ask the police.
* Aswad (Ventura Theatre, 26 S. Chestnut St., Ventura, 648-1888) Another roots reggae extravaganza sure to keep the dancers dancing, mon.
* Toad The Wet Sprocket (Charlie's) Mellow, yet intense, pop rock by those Santa Barbara locals with a pair of albums to their credit.
* Jellyfish (The Pub, UCSB) The show of the week with vocals as good as anyone. Jellyfish's "Bellybutton" sounds as if it could've fallen off the Beatles "White" album.
* Rob Rio & The Revolvers (Alexander's, 1050 Schooner Drive, Ventura, 658-2000) Don't care about the Rams and you just have to dance? This week's Blue Monday concert features even more rock-and-roll royalty--Rob Rio, "King of the Boogie Woogie Piano."
* Plato's Cat (Charlie's) Slick pop rock by a trio of philosophical feline fanciers.
* Michael On Fire (Hungry Hunter, 487 N. Moorpark Road, Thousand Oaks) This guy is so good you'll be stuck trying to invent some new adjectives to describe it all.
* Lion I's (Hornblower's, 1559 Spinnaker Drive, Ventura, 658-2202) Even the fish in the harbor will be dancing.
* Dramarama, Clyde (Ventura Theatre) They have three albums of raunchy and raucous rock, rock, rock. It's worth the price of admission for their traditional concert-starter, "Stuck in Wonderamaland."
* Raging Arb & The Redheads (Charlie's) This is the real Halloween party, just ask the police, again.
* Spencer The Gardener (The Ketch) Hook-filled Santa Barbara pop rock that begs the musical question, why are there so many good concerts on the same night?
* Official Resistance (Alex's Cantina, 633 State St., Santa Barbara, 966-0032) They've got enough tattoos to fill three Hell's Angels chapters, but they rock a lot harder.