Tribe is not a bunch of normal, boring musicians trying to be weird; it's a bunch of weirdos trying to be normal. At this they fail, thank God, zigzagging frantically from one genre to another (and pausing to creatively mangle the occasional Woody Guthrie song), but always sounding exactly like themselves. Certain constants do prevail: Andrew Robb's mad, yowling singing style, Mike Christensen's love affair with the high end of his bass, etc. But they're mostly held together by a very special indefinable vibe that renders questions of technique irrelevant (this band is loose, not tight--which has its advantages). Tribe's inability to fit into any current trend forces them to be one of the most original bands in town. Saturday, Avalon NitecIub, 959 W. Belmont; 472-3020. Next Friday, September 11, Cubby Bear, 1059 W. Addison; 327-1662.