The formation of (very) slowly rotating stars

Some main sequence stars are known to rotate with periods of a century (some probably even longer), while some otherwise identical stars rotate in a fraction of a day, or at any possible period in between. What's behind this factor 10⁵ in rotation periods? The longest periods are the most intriguing, since it turns out that there is very little that can spin a star down to these periods once it has formed. Instead I argue that the slow rotation of these stars is a possible outcome of the formation process itself. This is somewhat counter to the standard picture of star formation, as informed by observations of the T Tauri stars.