The I Ching (pronounced "Je Jeng", meaning "Book of Changes") is a 5000 year old Chinese book of divinations regarding future events. As the causal events leading up to the future develop, the I Ching is supposed to be able to "pick up" on the ebb and flow of the Tao as it expresses itself. By meditating on the question to be asked, calculating the lines and then following the advice of the result the I Ching gives the best route to take to get the best outcome (or avoid the worst).

These divinations are constructed using hexagrams which are each made up by combining two of a possible eight trigrams. These are calculated line by line either by flipping coins or the more traditional drawing yarrow sticks. There is an oracle on Everything2 if you want a computerised version.

The most basic component of a hexagram are the lines, either a full line (===) for Yang or a broken line(= =) for Yin. These are grouped into groups of three, and produce 8 possible trigrams.

 
       ------            --  -- 
Ch'ien ------ K'un -- --
------ -- --

-- -- ------
Chên -- -- Sun ------
------ -- --

-- -- ------
K'an ------ Li -- --
-- -- ------

------ -- --
Kên -- -- Tui ------
-- -- ------

These were given the following meanings:

The trigrams are then combined one on top of the other, and form a particular order, called the King Wen sequence. King Wen lived around 1150 B.C. The meaning of this sequence has been commented on by many, but non so "creatively" as Terrence McKenna and his Time Wave theory...

To construct the lines, flip a coin 3 times. A heads is 2 (earth) and a tails is 3 (heaven). The total will be 6, 7, 8 or 9. The lines are constructed bottom to top. 6 and 8 are broken lines (= =), 7 and 9 full lines(===). 6 and 9 are "changing lines", so once you've made your first hexagram, make a second using the first, but any changing lines become their opposite. If there are changing lines, you'll need to read the corresponding latter part of divination result.

Use Everything I Ching if you want a quick way of doing it, although personally I like constructing the lines.

The following is a handy look-up table for the order of the 64 trigrams.

---->   C  C  K  K  K  S  L  T
Upper   h  h  a  e  u  u  i  u
        i  e  n  n  n  n     i
Lower   n  e  n
||      n
\/

Ch'ien  1  34 5  26 11 9  14 43
Chen    25 51 3  27 24 42 21 17
K'an    6  40 29 4  7  59 64 47
Ken     33 62 39 52 15 53 56 31
K'un    12 16 8  23 2  20 35 45
Sun     44 32 48 18 46 57 50 28
Li      13 55 63 22 36 37 30 49
Tui     10 54 60 41 19 61 38 58

The following is the in-order sequence of hexagrams that make up the King Wen Sequence of the I Ching.

  1. Ch'ien, The Creative
  2. K'un, The Receptive
  3. Chun, Difficulty at the Beginning
  4. Mo'eng, Youthful Folly
  5. Hsu, Waiting (Nourishment)
  6. Sung, Conflict
  7. Shih, The Army
  8. Pi, Holding Together (union)
  9. Hsiao Ch'u, The Taming Power of the Small
  10. Lu, treading (conduct)
  11. T'ai, Peace
  12. P'i, standstill (stagnation)
  13. T'ung Jo e'n, fellowship with men
  14. Ta Yu, possession in great measure
  15. Ch'ien, Modesty
  16. Yu, enthusiasm
  17. Sui, Following
  18. Ku, Work on What Has Been Spoiled (Decay)
  19. Lin, Approach
  20. Kuan, Contemplation (View)
  21. Shih Ho, Biting Through
  22. Pi, Grace
  23. Po, Splitting Apart
  24. Fu, return, the turning point
  25. Wu Wang, innocence (the unexpected)
  26. Ta Ch'u ,the taming power of the great
  27. I, the corners of the mouth (providing nourishment)
  28. Ta Ch'u ,the taming power of the great
  29. K'an, the abysmal (water)
  30. Li, the clinging (fire)
  31. Hsien, influence (wooing)
  32. Ho'ê'ng, duration
  33. Tun, Retreat
  34. Ta Chuang, the power of the great
  35. Chin, Progress
  36. Ming I, Darkening of the light
  37. Chai Jo'ê'n, the family (the clan)
  38. K'uei, opposition
  39. Chien, Obstruction
  40. Hsieh, Deliverance
  41. Sun, Decrease
  42. I, Increase
  43. Kuai, Break-through (Resoluteness)
  44. Kou, Coming to Meet
  45. Ts'ui, Gathering Together (Massing)
  46. Sho'ê'ng, pushing upward
  47. K'un, oppression (exhaustion)
  48. Ching, The Well
  49. Ko, Revolution (Molting)
  50. Ting, The Cauldron
  51. Cho'^e'n, the arousing (shock, thunder)
  52. Ko'ê'n, keeping still, mountain
  53. Chien, Development (Gradual Progress)
  54. Kuei Mei, The Marrying Maiden
  55. Fo'ê'ng, abundance (fullness)
  56. Lu, The Wanderer
  57. Sun, The Gentle (The Penetrating, Wind)
  58. Tui, The Joyous, Lake
  59. Huan, Dispersion (Dissolution)
  60. Chieh, Limitation
  61. Chung Fu, Inner Truth
  62. Hsiao Kuo, Preponderance of the Small
  63. Chi Chi, After Completion
  64. Wei Chi, Before Completion
Most of the informationis available in the Richard Wilhelm version of the I Ching, which is the most popular translation, available from Penguin Arkana. It also has a forwards by Carl Jung.