It's been several months since I mailed in my tax forms and was subsequently hit with a "failure to file" claim (note: send those things in by certified mail). Apparently, they lost the forms. So by their reckoning, I owed $10,250 plus penalties.
Welp, this whole thing has been a barrel of laughs. From the look of things, they lost the forms but somehow found the check, which was in the correct amount of $5,129. So I sent them the forms again. Over the ensuing months, they determined that I owed them a one-dollar penalty - but they owe me several thousand dollars, which they say that they will refund at some point next month.
They will deduct my one-dollar penalty from the refund. I thought about fighting that, too - after all, it's not my fault that they managed to lose the paperwork - but there comes a time when you just have to say "screw it".
At least it seems to be winding down.