If you have teens and you haven't saved much for college, there are some options. None of them is pretty.
First, don't attempt any financial heroics without professional help. This will involve taking a long, hard look at your retirement situation. If you are young(ish) parents, intend to work to 65 or beyond and have already built up a solid nest egg, you may be able to do some shifting into 529s. You'll need to pay attention to gifting rules (there is a thing called "super funding" for college accounts, which means there can be a one-time gift of $65,000 per parent per child) but that gift precludes anything else being given to that child's account for five years.
Contact a financial planner or accountant, think through your own well-being and don't do anything rash. Here's an article about a family with a senior and sophomore and no college savings yet. See what a professional recommends.
Good luck, to us all.