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.