Here we get a list of the land animals that the Israelites are allowed to eat.
Kosher animals have divided hooves (split in two). They also chew the cud, meaning that food goes into the animal's stomach and then returns to its mouth to be chewed one more time. Pigs' hooves are divided, but they don't chew the cud, so they can't be eaten. Sorry, pork lover.
One rule definitely wouldn't be enough, so how about some more? If you have a hankering for some seafood, you can't eat shrimp—they don't have fins or scales, which makes them unclean.
Also, don't eat anything that has died of natural causes.
And here it is, folks. The verse upon which observant Jews base their separation of milk and meat. The Bible tells us not to boil a kid (a baby goat) in its mother's milk. For an interesting discussion of this law and the Hebrew language, check out "Should Cheeseburgers Be Kosher?"
If you harvest grain, wine, or olive oil, 10% of it belongs to God. Bring it to the temple and it will help fund the priestly order.
If the temple is too far away for you to bring your crops, then turn those crops into money and you can buy something to sacrifice. (Hundreds of years later, this rule caused a lot of problems for Jesus in John 2.)