Inspired by the Python project from http://musicmachinery.com/2010/05/21/the-swinger/ , I took 2 tunes anybody would know for sure. I applied FleXoR Granular Delay modulated by wave-shaped Ramp MKII to a couple tracks. Brings some different grooves - and yes, artifacts. More "proof of concept" than anything - would be blasphemy to try and improve Billie Jean, for example =]
Here's how it works: The granular delay delays incoming audio, then the delay time is modulated with a cycling wave that loops every bar. Half of the bar, the delay time decreases, and half of the bar, the delay time increases. This results in a slower playback half of the bar, and a faster playback the other half of the bar...Then the shortened or stretched audio is perceived as a swing or shuffle.