It’s a showdown of unadulterated, heartfelt earnestness v. mind-melting, irony-clad absurdism tonight on Cannery Row. San Diego’s Americana-imbued indie-rock act, Delta Spirit, make the sort of unapologetically sincere, wistful but insistent rock ‘n’ roll that almost lands south of the Cringe Line. Efforts like June’s History From Below, however, are done well enough that they earn the title “endearing” over “embarrassing.” Ramshackle instrumentation and the gravelly, melancholy bark of frontman Matthew Vasquez betray a deep affinity for the likes of Neil, Dylan and The Boss — the trifecta of heartland earnestness — and Delta Spirit even feature a couple of former members of the Christian emo outfit Noise Ratchet. How’s that for earnest? It might be argued that Tim Heidecker and Eric Wareheim, on the other hand, haven’t produced an ounce of earnest, ingenuous material between them. The creators of Adult Swim’s Tom Goes to the Mayor and the mind-freaking cult hit Tim & Eric Awesome Show, Great Job! are known for such characters as the hair-plugged, marinara-stained spook master Spagett and the lecherous, shrimp-eating, white wine-swilling Beaver Boys. Tim & Eric’s live show — labeled “Chrimbus Spectacular 2010” on this go-round — features many of inanimate-object-humping, mad-mugging bits, skits and pranks fans have grown to awkwardly embrace, plus a few new surprises. Perpetually offensive insult comic and fellow high-concept low-brow enigma Neil Hamburger opens. So which is it? Heart-sleeved, foot-tapping indie rock, or head-scratching wackadoo antics?