Apple to Apple Rules
To start, each player is dealt 7 red noun cards. One player (the dealer) is chosen to be the judge for the round and draws a green description card instead of receiving any red noun cards and places it on the table, reading off what's on the card. Except for the judge, each player must decide which of her red noun cards they think matches the most, and place her choice face down on the table. The judge shuffles the cards and reads off the different nouns and chooses the winner of the round, who gets to keep the green card as a point. All the cards are collected, and play continues clockwise, with each player getting a fresh hand of 7.
Creating Decks
It is possible to create your own Apples to Apples game decks. The words and phrases won't be completely the same, but that's fine, seeing as they'll all be words that resonate with you. You're going to need to create at least as many green cards as rounds of the game you intend to play and for the red cards seven times the number of players times the number of rounds--in other words, you're going to need a lot of cards.
One good way to make the cards is with green- and red-colored card stock. Twenty-five green cards and 100 red cards should be sufficient to start, seeing as you can always make more later. 100 red cards allows for a wide variety of combinations and will make it less of a big deal when they have to be reused as the game continues.
For each of the green cards, write a description of some kind. Keep it brief: "adventurous," "terrifying," "hilarious" or "well- traveled" are examples. For each of the red cards, really vary the content of the noun or action. Use actors, politicians, places, items, household chores.
Since it's a homemade set, you can have fun with it and include the names of people that the people you'll be playing with will know or local activities you all engage in. You could even make a theme for an organization or group. If you are making it for an English department, use authors and books. For a family reunion, use family members and references to family jokes.
Impromptu Apples to Apples
If you want to play Apples to Apples on the fly at a party, but don't have a game on hand, you can try this less formal method. Have all the players (except the judge) come up with seven nouns or specific actions as above and write them on sheets of paper. Mix all the sheets together and deal out seven a person (minus the dealer/judge) as usual. Have the judge come up with their own description. Play continues normally. After the round, each player (minus the new judge) writes down seven new nouns. The new nouns are mixed in with the old nouns and play continues until there is a winner.