If you've been coming up short on the taxes you owe, there is some relief and a way to avoid steep fines associated with late or insufficient payments, as well as a way to avoid criminal charges associated with failure to pay. That relief comes courtesy of tax amnesty programs. These programs are most often administered at the state level.
Many states have had an amnesty program over the years, but not all. To find out if your state is offering such a program this year, you should contact your state's department of revenue or official taxation body.
You're eligible for these programs if you have either missed the deadline for payment or if you have underpaid. You have to take advantage of the program before an investigation into your past-due account is underway to remain eligible.
To take advantage of this "get out of hefty fees" program you have to pay all the taxes and interest by the deadline established for the amnesty program in your state. From there, you will usually sign an agreement that verifies that you will pay taxes on time in the future, though you should always consult with a trusted tax adviser or professional before moving forward, especially before you sign anything.
The tax amnesty period isn't a long one, but it is a chance to get out of astronomical late fees or worse. Be aware that not all programs will waive the late fees entirely; some just reduce them.
If you are eligible for amnesty and don't take advantage of it, you could be subject to penalties just for not opting to participate in the program. California is one of those states that has established stiff penalties for those who could participate but choose not to. In some cases, the interest penalties can double.
If your state doesn't offer an amnesty program, have no fear. States would far prefer to recoup some of these taxes, so they have established other ways to collect their monies. In some cases, even though there isn't an official "amnesty" process of sorts, the state may have an ongoing program by which complying with paying back taxes is promoted. Again, this is case by case, so it's best to check with your state's taxing body.