Calpers, the pension fund  for state employees, has lost a huge bet on real estate.  By federal law, tax payers get to make up the losses to the fund.  Huffington Post has a good summary :

Calpers, the giant pension fund of the California Public Employees' Retirement System, which heavily invested in the same sort of "real assets" as Harvard. Leveraging its own funds, It bought so much undeveloped real acreage, that by 2008 it became the largest private land owner in America, and as the real estate bubble expanded, it marked up the notional value of its portfolio accordingly. Then came the subprime debacle, and the real estate bubble imploded, leaving Calpers with unsalable land and, because of its borrowed funds, a 103% loss. Together with other losses in hedge fund and conventional investments, Calpers found that it had lost nearly 40% of the value of its entire pension fund. In Calpers's case, it had little choice other than to realistically report its enormous losses since it had pension obligations that now might require raising money from local governments in California.

That 40% loss represents an $80 billion loss, twice the size of the current budget deficit bedeviling Sacramento.

Capitol Weekly reports that  "losses at the fund could require the state to [contribute] money after 2010", so these numbers probably aren't part of the current budget process.