The futures market is a highly liquid market that is different from the general stock market. While the stock market operates in real-time, the futures market operates on a time-delayed basis. This is due to the nature of a futures contract: it is an agreement between a buyer and a seller to exchange a specified asset that is set both in terms of quality and quantity at some point in the future. For this reason, futures are not so-called direct securities, such as stocks or bonds. Technically speaking, futures are actually derivative contracts; that is, the contracts derive their value from the exchange of some common asset.
Futures contracts can be traded bought and sold for any asset, from gold to orange juice. Assets that are traded using futures contracts are typically some kind of commodity; rarely do these contracts have to do with any other derivative contracts, or even with stocks, although the practice is not unheard of. Here are some additional details about the nature of futures contracts: the buyer of an asset takes a long position, while the seller takes a short position. The price of a given contract is exclusively a result of two different interacting forces: supply and demand and the number of competing sell and buy orders at the time of execution of the contract.
Needless to say, trading futures contracts is a risky business for those who do not know what they are doing. Futures have the potential to rob you, hand-over-fist, of all your money and then some, so approach this market carefully.