We all know the "unplugged" fallacy—that singing someone else's well-known song slower and acoustically will unearth new, deep meanings. Suuurrre it will. What's most depressing about this idea, besides how easily it afflicts the well-meaning well-off, is that this stuff is usually so po-faced precious you just want to hawk a loogie at it.

But what if the song was fairly precious to begin with? Take John Mayer's "Free Fallin' (Live at the Nokia Theatre)" (Columbia). If Tom Petty is, as Simon Reynolds drolly put it, "a louse on Dylan's scrotum," Mayer is merely Dave Matthews's cuter, funnier, more cadlike younger brother, and here he takes a song that was pretty full of itself to begin with and simpers it up but good. Well, not "good," but you see what I mean.

The Last Shadow Puppets—the side band of Arctic Monkeys' Alex Turner and the Rascals' Miles Kane—at least make the attempt to rouse the listener with their version of Rihanna's "SOS" (MP3), recorded in session for Jo Whiley's BBC Radio 1 show back in April. They do so, unfortunately, by indie-ing it up: dragging the tempo, adding organ and skittering guitar, whispering some lines "spookily," and making the whole thing "menacing." Good thing they did, too: Now people who never listen to actual pop music can pride themselves on knowing it can contain, whaddaya know, "dark undertones." Wow, dude.

At least they didn't do Rihanna's "Umbrella." But who'd have imagined the preceding song to achieve multiple-cover ubiquity, Gnarls Barkley's "Crazy," would actually benefit from yet another remake? Especially since it's by Violent Femmes (Secret Life Of), a band that haven't done anything of real note in a quarter-century. But maybe Gordon Gano's agitated whine and folk-punk strum just needed better songs than the ones he'd written since VF's debut to make us care, and now he's found one. Everyone else found it two years ago, of course. But Gano sounds thrilled about it, and with a cover version, that can make the difference.