Broke mine a couple days before xmas (similar to yours - small fracture, no displacement) and separated my AC joint (which, according to my brother who's an ER doc, is the more serious injury - bones heal quickly compared to soft tissue). I was able to ride the next day. Pretty much anything that provided support to my arm/shoulder was fine (such as riding with my hands on the tops of the bars), but moving was horribly painful. Never used a sling, but I couldn't even hold a cup of coffee with the arm for about a week.

It's been almost a month and I can do most things, but some silly things are just too painful, like sleeping on the same side as the injury. I also found that using my arm as much as possible (but within reason), while uncomfortable, seems to be helping it heal faster. However, I couldn't possibly swim, as range-of-motion is pretty painful in some positions. Running? Probably, but I don't run :)