For those of us who&rsquo;ve sat in a mostly empty jam session at the Mutual Musicians Foundation in the 18th and Vine District, wondering what the future held for Kansas City&rsquo;s historic home of jazz, the arrival of the radio program &ldquo;12 O&rsquo;Clock Jump&rdquo; has been a huge, gratifying shot in the arm.</p><p>Since the Theater League-produced variety show began airing live from the top floor of the Foundation this summer, the joint has been jumpin&rsquo; indeed, with standing-room crowds providing exactly the kind of audience response that Theater League director Mark Edelman had hoped for.</p><p>&ldquo;My favorite part of it is that there&rsquo;s a diverse audience,&rdquo; Edelman says. &ldquo;Nobody&rsquo;s keeping anybody out of 18th and Vine over a dress code.&rdquo;</p><p>&ldquo;Twelve O&rsquo;Clock Jump,&rdquo; airing live at midnight Saturday nights on KCUR, is still a work in progress, and I can&rsquo;t help but wear my critic&rsquo;s hat when listening to it, which we&rsquo;ll get to in a moment. But I have to agree with Edelman about the crowds. The night I attended a broadcast, the room was mostly young and white. But it was far from monochromatic. And it was anything but nonchalant.</p><p>Edelman might as well have left the &ldquo;APPLAUSE&rdquo; sign back at the shop because, on that night at least, the audience didn&rsquo;t need any prompting.</p><p>Music director Joe Cartwright paid tribute to the pianist Oscar Peterson on Peterson&rsquo;s birthday with showy performances of &ldquo;Over the Rainbow,&rdquo; &ldquo;Night Train&rdquo; and other numbers that were worthy of the master. </p><p>Another highlight was the appearance of an artist not even billed on the program: &ldquo;Tonight Show&rdquo; trumpeter and Grandview native Mark Pender, who told the crowd about getting his start in a jazz ensemble three decades earlier in that very room at the Foundation, then tore into the challenging bop standard &ldquo;Sho Nuff.&rdquo;</p><p>The music was solid, though when I listened to the broadcast later, I thought the string bass sounded a lot quieter than it did in the room. Regarding the comedy, I was not so enamored. Edelman recruited writers from across the country to add some laugh breaks to the show. And to be fair, the sketches that night were certainly crowd-pleasers &mdash; even a pun-filled version of the three-guys-walk-into-a-bar joke did well. </p><p>But I remain unconvinced that this variety-show staple belongs in an after-midnight program. A show like &ldquo;12 O&rsquo;Clock Jump&rdquo; ought to have a nightclub feel; instead, it sounds kind of like a midday show that got bumped to the graveyard shift by a churlish program director.</p><p>Which, by the way, couldn&rsquo;t be further from the truth &mdash; KCUR&rsquo;s program director Bill Anderson loves &ldquo;12 O&rsquo;Clock Jump&rdquo; and will air it for as long as Edelman wants to produce it.</p><p>&ldquo;I&rsquo;m in it for the long haul,&rdquo; he says.</p><p>Still, one eternal truth about public radio is that there are no &ldquo;Desperate Housewives&rdquo; on the schedule &mdash; no instant, out-of-the-box hits. </p><p>Even the most popular shows were once a work in progress. KCUR general manager Patty Cahill will tell you it took years before she agreed to air programs like &ldquo;Car Talk&rdquo; and &ldquo;Wait, Wait&rdquo; because they just weren&rsquo;t ready.</p><p>So no one is expecting an overnight sensation here, so to speak.</p><p>&ldquo;&ensp;&lsquo;12 O&rsquo;Clock Jump&rsquo; has not quite found its voice, but the production values and content creation are top-notch,&rdquo; Anderson says.