A Slack Day

Some time ago prof. Andrew McAfee had an interesting post about what's most important for the success with Enterprise 2.0. One of the things he mentioned was:

Slack exists in the workweek

Slack... This term has been buzzing in my head for some time. For one because of the fact that there hasn't been much slack in my agenda the last couple of weeks... But also because many people say they are "really busy" and "don't have time for social media".
I organize slack. I work from home regularly if I really want to concentrate on something, like reading and writing (a blog post). Even though I work hard from home I experience it as slack. And when I'm at work I almost always make sure I have one or two hours to read feeds and reflect on them (possibly leading to a blog post, tweet, etc.).
A couple of weeks ago we had a cleaning day at the office. We organized slack for a specific reason. I love these days. Everyone is in a different mode, we're all working on the same thing and there are clear results at the end of the day.
I was wondering: do we need 'a slack day' every week (excluding Saturday and Sunday...)? One day a week for us to sit back, reflect on your job, read inspiring and thoughtful information and share your insights. Or am I wrongly tackling a deeper cultural issue with an organizational solution? I'd love to hear your thoughts.

UPDATE 14-10-2011: Good quote and post about slack.