So here are the rules:

Use a standard set of Rummikub tile for this game.

Take out the Jokers and shuffle the tiles.
Set the tiles face up in a square of 5 * 5, 7 * 7 or 9 * 9, depending on the difficulty level you want. Leave some margin around each tile.
(The remaining tiles are left out, facing down).

Two players sits on opposite sides of the square.
They start the game by taking one tile from the row closest to them.
Then they take one tile from the next row, either strait ahead, one to the left, or one to the right.
Both players plays simultaneously, so they should take the tiles as fast as they can.
When the first player takes the tile from his last row (which is the other player's first row), the game stops.

At this point, The players sums their tiles numeric values.
The player with the highest score wins the round.

Sample game play (7 * 7):

Player 1                        
4   3   11  13  3   9   8
12  7   5   4   10  7   6
2   12  1   12  7   8   10
8   13  1   9   12  2   11
13  11  7   10  2   4   4
5   6   9   3   9   8   11
5   13  5   10  2   6   1
Player 2                        

P1: 13
4   3   11      3   9   8
12  7   5   4   10  7   6
2   12  1   12  7   8   10
8   13  1   9   12  2   11
13  11  7   10  2   4   4
5   6   9   3   9   8   11
5       5   10  2   6   1
P2: 13

P1: 13, 10  
4   3   11      3   9   8
12  7   5   4       7   6
2   12  1   12  7   8   10
8   13  1   9   12  2   11
13  11  7   10  2   4   4
5       9   3   9   8   11
5       5   10  2   6   1
P2: 13,6

P1: 13, 10, 12  
4   3   11      3   9   8
12  7   5   4       7   6
2   12  1       7   8   10
8   13  1   9   12  2   11
    11  7   10  2   4   4
5       9   3   9   8   11
5       5   10  2   6   1
P2: 13,6, 13

and so on...

Optional rules - Include the Joker (s):

Option 1. When a player takes a joker, at the end of the round it's replaced by one of the left out tiles (without knowing what's the value of this tile).

Option 2: When a player takes a joker, they can replace one of their tiles with one of the opponent's tiles. The joker doesn't carry score and can't be replaced.
This option means you have a really big advantage if you take a Joker - because you can replace your lowest tile with the opponent's highest tile.

Blind version - play with the tiles up side down, so you can't see what cards you're taking. A combination of speed and pure dumb luck.

Another possibility: When the board is large enough, four players can play, each on every side of the square.

So, would you play this game?