If you know about Harmonized Records, the enterprising li'l indie imprint based in Mebane, you're already an upstanding citizen of the Jam Band Nation. And you're no doubt aware of this weekend's Harmonized Records Showcase at Lincoln Theatre in Raleigh, a de facto gathering of the tribes: five swirling improv bands shooting out sparks for two nights in a friendly atmosphere where listeners, dancers and musicians will cavort and commingle. For those of us stuck on the outside looking in, however, this is also the perfect time to climb aboard the jam-bandwagon--and figure out what grooves and what doesn't. The lineup Friday (Oct. 4) features the Motet, a mischievous Colorado combo that mixes '70s-style fusion with undercurrents of samba, and ULU, a sax-meets-organ New York band with R&B tendencies. Saturday's show headlines jam super-band Garaj Mahal, a fiendish foursome fronted by guitar wiz Fareed Haque, and co-stars prog revivalists Perpetual Groove and Lotus, space cowboys who trance and dance. Check out harmonizedrecords.com for more truths--and a guaranteed rush of good karma. $10 Fri., $15 Sat. in advance; $20 both.