Demetri Martin: Person, E4<br/>Important Things with Demetri Martin, E4<br/>Spiral, BBC4

For some years, American indie culture has been riddled with quirk: an appealingly odd, super-hip sensibility that became mainstream thanks in large part to the movies of Wes Anderson.

Until now, quirk's foremost practitioners in the field of television comedy have been Flight of the Conchords, New Zealand-born, New York-based folk musicians who lend their name to a discreetly surreal sitcom. HBO, which produces Conchords, recently launched a quirk-based competitor, Bored to Death, starring Anderson regular Jason Schwartzman as a novelist and ineffectual PI.

In both shows, the protagonists are neurotic, romantically challenged, young New Yorkers with artistic aspirations. Their problems are invariably low key, and their settings aspire to the delicious detail of Anderson's production design aesthetic. Similarly sensitive chaps lead the casts of recent indie romances (500) Days of Summer, Adventureland and Nick and Norah's Infinite Playlist. Demetri Martin, a fresh addition to the British broadcast schedule, is the stand-up comedy incarnation of this stock quirk character.

Last week E4 screened Martin's Comedy Central stand-up special Demetri Martin: Person, closely followed by the first episode of Important Things with Demetri Martin ("a show", he assured us in his opening monologue, "about things"). A former skateboarder from New Jersey, Martin is The Daily Show's "Senior Youth Correspondent", and the star of Ang Lee's latest movie Taking Woodstock. His comic persona is charmingly faux naïf: men find him unthreatening; women want to stroke his floppy hair and discuss the Decemberists.

Person was a series of mostly disconnected observations without any specific remit, interspersed with amusing title cards (very Anderson-esque); musical interludes (Martin plays guitar, harmonica, keyboards and bells simultaneously); and the flip charts that are his trademark. Among the more amusing personal data demonstrated in his flip-chart "findings" was a graph of the cuteness of a girl versus his tolerance for "listening to her talk about how intuitive her cat is".

Important Things followed a similar format, with a couple of sketches sprinkled on the confection for good measure. Martin's schtick is gentle and inoffensive, with nary a dick joke in sight. The overall effect is pleasant, but it grows a tad tepid over time – a feeling familiar to anyone who's ever spent too long in the bath reading the latest issue of McSweeney's. Like Conchords, Martin's performance is studiedly unstudied, and his humour about as edgy as an orange. ("I think they named oranges before they named carrots ..." he mused.)

The comic's recurring obsession is with the foibles of language, and if he were Chris Rock, he might have something seriously funny to say about the cultural significance of, for instance, the racial slur. But Martin is a diffident semiologist, surfing the not exactly perilous line between literal and accepted usage. Why are people called chocoholics, he wonders? (There's no such thing as chocohol.) And doesn't the phrase "cat person" suggest something rather different to a person who likes cats? "I saw a sign on this door," goes one of his finer jokes. "It said 'Exit Only'. So I entered it and I went up to the guy working there and I was like, 'I have some good news. You have seriously underestimated this door.'"

While I'm on the theme of language, I must applaud BBC4 for cultivating a sideline in smart, subtitled thriller imports. Recently the channel broadcast the original Swedish adaptations of Henning Mankell's Inspector Wallander novels, and now we have the second series of the superior Spiral, about the mildly baffling French legal system. It's tempting to give foreign dramas more credit than they deserve, since the language barrier can disguise clunky dialogue; but Spiral's first run was gripping, and this series – the third episode is tonight – shows every sign of being equally so.

Last week, Laure Berthaud (Caroline Proust), the tough female police captain, was in hot water with internal affairs after bashing a troublesome suspect with her baton. Her former lover, dashing barrister Pierre Clément (Grégory Fitoussi), was unable to help her, due to the machinations of his toadlike boss. Beautiful young lawyer Joséphine Karlsson (Audrey Fleurot) took on some unsavoury clients to pay her debts, and the unnerving but canny Judge Roban (Philippe Duclos) investigated a suspected gang rape with characteristic flair. Meanwhile, a murderous rapper continued littering the Paris housing estates with bodies.

The show's original French title is Engrenages, meaning not "spiral" but the more apposite "cogs": each character – be they a lawyer, a cop or a criminal – is a wheel in the dramatic engine. They operate with varying degrees of efficiency, many are worn with overwork, and some are in need of serious greasing. Happily, however, they'll be turning for another few weeks yet.