Help needed quick on garden variety "unfunded liabilities"

[John K. Taber]

I'm involved again in another argument on Social Security. The
pejorative "unfunded liability" has come up. I remember reading
somewhere that a lot of "liabilities" are unfunded. I seem to
remember an example like one's mortgage payments, or a 
corporation's payroll.

I'm checking with you guys because I want to avoid blundering.
Please give me examples of non-invidious unfunded liabilities.

Thanks

PS I hope Doug gets the list server working again.
--
Believe me, the most alarming of all novelties, the most wild
of all projects, the most rash of all attempts, is that of
rending us in pieces in order to preserve our liberties and
promote our happiness. -- Madison (Federalist XIV)