For 4 or more persons, the more the better.

(The game can technically be played with as few as 1 or two, but is not nearly as fun)

Warning: This game can be repeated for hours on end, possibly depriving partygoers of sleep and nourishment.

Equipment:

1) Table, or other flat playing surface, which can have people sitting all around it. It may be larger than such, but not smaller. If there are not enough people to sit all around it, the table must be situated so that all players can stand and walk around it.

2) Plastic cups. At least as many as there are players, but preferably many more.

Cup Specifications:
Cups are optimally between 4 and 5 inches tall. Diameter at the bottom is optimally 2 inches wide, and at the mouth 3 inches. Smaller or larger cups can be used as well.

Setup Option A)If the table is the correct size and provides enough seating for all players to be seated around it and be closely adjacent to each other, playes shall (obviously) sit around the table.

Setup Option B)If the table or playing surface is too large for all players to be situated directly next to each other in a full circle, players stand adjacent to each other along the table.

Each player begins with one cup in front of them, upside down. (For those who are unclear, where there to be any liquid in the cup, placing it upside down would cause the liquid to spill on the playing surface.) Extra cups should be stacked or set next to each other to the left of the leftmost player with a few scattered near other players(with Option A), or in the middle of the table (with Option B).

Play

There is a rhythm to this game, and all players must perform the motions in unison. When just learning, it may go slowly.

All players do the following…

For each statement, one net action is performed. This action is indicated in all capital letters.

CLAP
CLAP
TAP the top of the cup with your Right hand
TAP again with your Left hand
TAP once more with your Right hand
CLAP again
GRAB the bottom (currently up) of the cup with your right hand
Pick the cup up off the table and MOVE it in front of you (probably but not necessarily to the right) and let go of it, still upside down.
CLAP
With your right hand, GRAB the cup from the left. To do this, your hand will likely feel backwards and your elbow stick out.
With cup in hand, move your right hand back to its “natural” orientation, thus turning the cup right-side-up and off the table, and TAP the open end of the cup to your open left palm (be sure your left palm is ready and waiting a little ways above and to the left of the cup). Make sure your right hand holds on to the cup.
Bring the cup back down to HIT the table, where it should now rest, right side up, still held by your right hand.
Lift the cup once more, in a similar motion to the previous grab, this time extending the bottom of the cup toward your left palm. SWITCH hands by grabbing the nearby bottom of the cup with your left palm.
Keep the cup, now grasped by its bottom by your left hand, in the air for the time being. Move your right hand leftward, and use it to SLAP the table.
Leaving your right hand where it is, bring your left hand, with the cup, cross above your right hand, set the cup down near the person to your right, and RELEASE it.

Now you know all the motions needed for cupline. Try it a few times to get the hang of it.

The motions are done to a very specific rhythm, as follows…

There is a steady beat to the Cup Game. Imagine a metronome in your head. Each of the following lines counts as one beat of the metronome. If there are two actions in a line, they should take equal amounts of time to perform.

CLAP
CLAP
TAP, TAP
TAP
CLAP
GRAB
MOVE
<wait one beat with no action>
CLAP
GRAB
TAP
HIT
SWITCH
SLAP
RELEASE
<wait one beat with no action>

Repeat with the cup just passed to you from the person on your left.
Keep going indefinitely.

Though it personally annoys me, a person once suggested that the rhythm sounds like “This Old Man.” To get a better idea of the rhythm, you might hum it in your head as you try to figure out the rhythm…
<i.e. This Old Ma-a-an, he played one… he played knick knack on my thumb> with each syllable (including the tackily extended ma-a-an, standing for one of the aforementioned motions.

Once you have the hang of the motions, play with the whole group of people. All players should make the motions in unison, and there should be a nice rhythm coming from the sounds of the claps, slaps, hits, etc. This rhythm will mostly likely get faster naturally, until people can’t keep up and mess up. In this case, they either get out of the line or try to pick up with the rest of the group.

Variations:

A — Sitting around a table) If there are enough players to comfortably sit near each other around a table, play progresses nicely, with a continuous stream of cups passed in a circle. If someone manages to lose their cup, extras should be nearby in the middle of the table.

B — At a table that is too big) Players stand next to each other and begin play. If there are no extra cups, the player on the far left will be left without a cup for the second round, and must therefore walk briskly / run to the far right of the group, where he resumes with the cup left by the far right person. Play continues as such, resembling the train tracks in Gumby. If there are extra cups, a stack may be available for the person at the far left, so he does not have to run off right away (or cups may somehow be shuttled back to the person at the far left).