Flight of the Conchords is enduring a classic sophomore slump.

Flight of the Conchords is enduring a classic sophomore slump.

The series was the most pleasant of surprises when it debuted in the summer of 2007 - an amusingly quirky comedy that morphed into something greater when characters burst out singing joke songs as funny as they were catchy.

New Zealand-born musical comedy duo Bret McKenzie and Jemaine Clement expertly played dumber versions of themselves struggling to make it in New York. But the real-life Conchords are much more talented than their clueless TV counterparts, and their goofy musical numbers carried the show.

McKenzie and Clement started with a deep well of songs, but even before those first dozen episodes ran out, they were clearly scraping the bottom of the barrel. The first two episodes of Season 2 suggest that problem persists.

The series returned two weeks ago with one of the more underwhelming premieres in recent memory. The episode seemed like a complete stinker at first, but upon repeat viewings, only the songs fell short. You know it's bad when the first musical sequence is Murray (Rhys Darby) performing a humorless operatic number about rejection.

Last week's installment was closer to classic form, but even if "Sugar Lumps" and "You Don't Have to be a Prostitute" were a step up, they pale next to the Conchords' best. Let's hope the slow climb back to brilliance continues.