For a SubGenius, Slack can be anything you get or enjoy out of life that you don't have to work for or pay for , an approach where one stops trying to make things happen or exert control, and instead simply "allows" or "lets" favorable events to occur. Everyone is born with Original Slack, an ideosyncratic harmony with the flow of life which the unwitting Conspiracy of Normality is unceasingly trying to trick us into giving up, often as a Con-job in exchange for False Slack (anything you're sold or conned into that you have to work for or pay for, or the obligation of working or paying for it).
I just had a the most Slack-filled (week/day/hour) -- everything just fell into place and "accidentally" went my way, and I didn't have to lift a finger or pay even one red cent to make it happen that way. Hell, I even found a $20 bill, so I'm money ahead! Talk about SLACK...
A vernacular of casual English in textual or verbal form, blending highly grammatical English with technical jargon, 1337/l33tspeak, hip-hop lingo and pop culture quotes/references as an expression of self-referential hip irony among geeks.
Variant of nigga blended with geek, used among geeks in reference to each other as an ironic but usefully race-neutral term of fraternal esteem, artfully evoking the dual, respectful-from-brothers/offensive-from-others aspects of both source terms. See geek speak.