Materials
To play this game, you need a deck of Uno cards and a pawn or other marker of some sort (a salt shaker or a pen cap will do just as well). You'll also need someplace to play it that's big enough to have a layout that's five cards across and five cards down, with a little extra space for the draw and discard piles. Oh, and you'll need two to four players.

Set-up
Shuffle the cards and deal out five to each player (don't show other players your cards). Next, deal out twenty-five cards face-up onto the table in a 5x5 grid; each player should sit behind their own side of the resulting rectangle; players should sit across from one another in a two-player game, but it's okay if they sit on adjacent sides. Set the rest of the deck aside as the draw pile, and leave room for a discard pile. Place the pawn (or salt shaker or pen cap or whatever) on the center card.

Play
Starting with the oldest player, each player may do one of the following:
   - Play a card and draw a card
   - Move the pawn (or salt shaker or... well, you get the idea
   - Discard and draw a card.
Play progresses to the left (to start out, anyway).

To play a card, take a card out of your hand and place it on one of the cards on the table that isn't covered by the pawn. The card must be able to be played as if it was in its own game of Uno (i.e. same color or same face value). After you play a card in this manner, draw a card from the deck to bring your hand back up to five cards. Play Draw Two, Reverse, Skip, and Wild Draw Four cards normally, but playing these cards do not create any special effects like they do in Uno (see the next paragraph, though).

To move the pawn, simply move the pawn one card horizontally, vertically, or diagonally. There is one condition, however. The pawn can only be moved in such a way that the card it is moving TO could be played on the card that it's moving FROM if it was a normal Uno game (i.e. the destination card has to be the same color or face value as the departure card). You may not move the marker to the last card it was on (e.g. after its first move, the marker's second move may not be back to the middle card). You can also move the pawn off an edge, in which case one or two people win (see the section on winning, below). If you move the marker onto a special card (Draw Two, Reverse, Skip, or Wild Draw Four), one of the following special effects happen:

     Draw Two: Draw two cards into your hand and immediately play two cards out of your hand onto cards that don't have the marker on them. You must play two cards, and while they don't have to be the two cards you drew, you can't discard unless there is absolutely no way to play the seven cards you have. It's okay to play a card on one you just played.

     Reverse: The direction of play immediately reverses. It stays that way until somebody else lands on a Reverse card, at which point it switches back. If there are only two players, this card acts like a Skip card.

     Skip: The next player loses his or her turn. In a two-player game, you get to go again.

     Wild Draw Four: Do the same thing as for a Draw Two card, but draw and play four cards instead of two.

To discard a card, just pick a card you don't want and put it in the discard pile. Then draw a card so that you have five cards.

Winning
Each player should have their own side of the 5x5 board. A player wins when the pawn moves off his or her side of the board. If the pawn moves off diagonally on a corner, the two players whose sides meet at that corner both win.

What to Do When You Run Out of Cards to Draw
If you run out of cards in the draw pile, you'll probably have a lot of cards in little piles on the board and a few cards in the discard pile. Just take all the cards on the board EXCEPT THE TOP ONES and shuffle them in with the discards. That's your new draw pile.
Additionally, some people have more than one Uno deck around the house. You can put two or more decks together into a super deck and so have more cards. This way, you won't have to collect cards as often.

Time Limit
Some people are going to hem and haw about their cards and what they're going to do on their turn. If this gets too annoying, put a thirty-second time limit on each player's turn and tell the strategists that it's okay to think on other players' turns, too.

Scoring
If one game isn't enough for you, you may want to play several games to see who the overall "winner" is. Score each solo win as two points and each shared win as one point. The first player to score five or more points wins.