More personal to me this year than others, as our due date is today/tomorrow, and we have a baby boy coming. For Christians, Advent is the pre-Christmas "get ready" season. For Gnostics, what does it mean?
I think it represents and opportunity to calm and center oneself in anticipation of the Incarnation, the awakening of the Light of Gnosis in the seat of the soul. If you're climbing the tree from Malkuth to Tipareth (as it's Hanukah today I thought I'd throw in a little Kabala out there) you need to make sure everything is balanced and stable. For me it's been more exoteric - getting baby stuff, getting on with house renos, catching up on work so there's time after baby arrives. But the point is pretty much the same for those gathering fresh straw for shopping-mall mangers. A place needs to be prepared for the Light to reside.
The idea of the Incarnation of Light/Return of the Sun at this time of year is as old as we are. The Christian invention of Advent is a very useful one, taking time to brace yourself for Everything Changing. Quite sane.
Such Churchitude brings out the heebie jeebies in many non-Christians. Why use the Catholic liturgical Calendar at all? What do we need the Mass for? Why the titles and vestments and trappings of those who hunted us down, imprisoned and massacred us?
Because it's not "theirs".
Remember, we're not making this up all of a sudden. For centuries, Gnostic ideas flourished in the Catholic church (I'm making a distinction here from "Christian" just to leave the Protestant and Orthodox tangent for another day). Countless Catholic Bishops died peacefully in their sleep after lifetimes of preaching and practicing Gnosticism. These people contributed, debated, and crafted much of what we see of Catholic liturgical culture today. The Cathars and Bogomils had Bishops. The Valentinians and Nestorians celebrated the Eucharist. And of course the Gnostic Revival of the nineteenth century also embraced the structure and liturgy of Catholicism, with a pneumatic understanding.
There is (and I believe was) also a deeper understanding of the pre-Christian nature of such things as the Offices, calendar, and indeed of the Eucharist itself. The Mass is the greatest and most accessible repository of the rituals of the western mystery tradition, reminding us that Divinity is real and present - here/now, not there/then. The roles of Deacon, Priest, and Bishop are echoes of Roman State Religion, while the elements of the Mass have roots in Mithraism and the the cults of Dionysus. Such things are the cultural heritage, if not the property, of the western world.