Congress faces a long do-list list as lawmakers return to Capitol Hill for the first time since September for what's known as a "lame-duck" session until the end of the year. Here are some the big issues  that they're set to address.

The biggest issue by far is what's known as the "fiscal cliff," which refers to the expiration of a series of economic measures (tax relief, reauthorization of unemployment insurance and the Job Creation Act of 2010) that are set to end this year.

If no agreement is reached, a series of tax cuts will expire and huge automatic budget cuts go into effect on Jan. 1. The combined actions could cost taxpayers an estimated $500 billion alone next year.

Democrats like President Barack Obama and Senate Majority Leader Harry Reid want higher taxes for those making more than $250,000 a year as a way to raise revenue.

House Speaker John Boehner and other Republicans have long opposed raising taxes, but recent statements by Boehner and others may mean some movement is possible.

Farm Bill -- The farm bill, which sets agriculture policy and funds the food stamp program, expired Sept. 30. Its expiration hit farmers immediately, especially dairy farmers who have not received their supplemental payments.

The Senate passed a bill but the House has not. Analysts say a one-year extension is possible during the lame duck session but a full-fledged five-year reauthorization is unlikely.

Airline Emissions -- The House already passed and sent to the president legislation that would exclude U.S. airlines from the requirements on emissions that the European Union has sought to impose on all planes flying to and from Europe.

Even with the temporary delay, Congress needs to act to ensure that U.S. airlines are not liable in the future for the EU-imposed tax. The Air Line Pilots Association said the cap-and-trade program could cost U.S. carriers $3.1 billion over 10 years.

U.S. Postal Service -- The broke quasi-government agency has been unable to meet $1.1 billion in payments for future retirees' pensions and is asking Congress to act.

The Senate passed a bill but the House has yet to act over wrangling over the high cost of the food stamp program. 

Polar Bear Carcasses -- One of the more random items Congress will take up is a sportsmen's bill that will decide the fate of 41 polar bear carcasses that hunters want to bring home from Canada as big-game trophies.

Intelligence/Defense -- Congress also faces deadlines to extend the post-911 surveillance bill, the Foreign Intelligence Surveillance Act, funding for the intelligence community and a bill to authorize defense spending and programs.