It's nearly midnight and the sweater/scarf/doll/etc. that you've been knitting away at is still drawing you on to knit "one more row", but ... wait! What's this? The pattern's telling you to do something that's just crazy insane - maybe it's saying "ssk" or "s1-k1-psso" or "cable 4 front". That kind (and not nearly so batty seeming) dear who gave you your first knitting hit is probably in bed, and the local yarn shops are all closed. Where can you turn for help?
YouTube is a great resource, but maybe you've tried to economize, ditching the home connection for your smart phone and streaming video is no longer in your budget.
Googling the specific pattern abbreviation may help get you to written directions.
Then there's actually buying knitting books and knitting DVDs. At the very least, if your internet is not reliable, you can still turn to these repositories of knitterly lore.
You can purchase direct from Interweave Press, and I strongly recommend the deluxe version of The Knitter's Companion. I'm waiting with baited breath for the technical issues to be resolved on their Android app version of this oh, so helpful reference.
Your local yarn stores and fair-to-middling large-sized book seller should have a section devoted to crafting, and knitting should be among them. Look the books over carefully. Some will be "knitters bibles", how-tos that cover everything from casting on to finishing and adding embellishments to your knitted pieces. Others will be pattern books, and these are likely to be sources of those strange instructions.
There is a third kind, a sort of blending of the two, which details a particular technique or aspect of knitterly lore and illustrates those aspects with patterns. (By the by, if there's a pattern you want to knit up contained within, please do check the publisher's site to see if there are any corrections to the pattern before casting on - after all, errata happens!)
As for DVDs, I've had more luck finding them - and decent reviews of them - at online retailers such as Knit Picks and WEBS.
Hoping this helps spark ideas and leads. Feel free to add links to your favorite repositories of knitterly lore!