Kokkuri-san is a game that crops up in quite a few anime and J-horror movies. You probably have seen Kokkuri-san in the semi-popular movie Kokkuri or in xxxHolic as "Angel-san". It's known by a lot of different names, and seems to get a new one every few years.
The current incarnation stems from the import of the Ouija board: a large piece of paper with the hirigana alphabet, numbers, yes/no, and a torii gate drawn on it, which is manipulated with a coin or some small object (or three fingers close together). The old version has many variations, but one may be three ohashi propped up against one another in a rice bowl (an offering to the dead; why you should never stand your chopsticks in your rice). Then, a chopstick will move to indicate an answer.
狐(ko fox) 狗 (ku dog) 狸 (ri raccoon or tanuki) さん (san in this case, a gender-neutral honorary suffix, like Mr. or Mrs.). The magic and trickery of a fox, the loyalty of a dog, and the tanuki, a bringer of fortune, all in one spirit-game. Like Ouija (literally, yes-yes), it is said that if you fail to play the game properly, you can become possessed or have ghosts wandering about, following you and bringing you harm. Because you summoned them, and they cannot leave; one also presumes that no one fed this ghost or gave it something for showing up, and it's bad manners to not at least offer a guest some tea.
I think the paper version of this game is the most popular now, probably because it gives better 'answers'.
Make a brand-new Kokkuri sheet each time. It has a torii gate, letters of the alphabet, yes/no, numbers, and sometimes entrance/exit. The layout is different each time. Sometimes it's the letters in a big circle around the torii; others, it's a hirigana chart. I made one for reference (it's in Japanese, though). I made this one large enough to print, I think, but make sure to set it to fit your paper layout.
Then, gather at least one other friend. Traditionally, it should be three people. Open a window or door to the outside so that the spirits attracted by Kokkuri-san can join you. The torii represented on the paper is the gateway from the spiritual world, too. Everyone must place their finger on a 10-yen coin, or put an index finger from each person in a very tight circle, careful not to break their connection (this is why a coin is much easier!) over the torii to begin.
Call the spirit by asking "Kokkuri-san, Kokkuri-san, if you are here, please move this coin!" This may take a few tries. Once Kokkuri-san has made it's (their?) presence known, you can ask them questions. The answers will be spelled out, so maybe another person has paper and pencil handy? But keep in mind that tanuki and foxes are tricksters, either to teach or to tease, so don't always take it so seriously... but also be open to an answer you don't like.
At last, ask Kokkuri-san to leave by saying, "Kokkuri-san, Kokkuri-san, please return home!" You might want to thank them, to encourage them not to stick around out of spite. After all, they did take their time to come. The coin should move to yes or 'exit'. If it does not, be more firm. Or, you know, call an exorcist.
It is customary to destroy the paper once Kokkuri-san has left, destroying the connection back into this world. After all, you shut the gate after the guest has left! Then, you must spend the coin used the next day, or preferably, the same day. Perhaps on a protective amulet against ghosts?
Of course, it is a superstitious game. The famous Dr. Yokai explained it himself, although he attributed the game's "working" to 'human electricity', supposedly. Maybe human subconscious spirit or intentions? Inoue Enryou was a famous Buddhist during the mid-late 1800s, and lived through the beginning of the 20th century, when Kokkuri-san first started becoming adapted to Ouija-style. Of course, this style of writing-game has been around for thousands of years, with first written records mentioning them in China near 1100CE, but at the time, Western things were popularised in Japan, giving us the Kokkuri-san we know today.