UNO Speed Rules
Parenthacks had a post on Making up New Rules for Card and Board Games and it reminded me of a version of Uno we used to play with a group of teenagers back before my kids were born. Basically we added three simple rules, but the effect was to create a game that was fast a furious and very engaging.
The first rule was that if someone played a Draw card on you, you could play another draw card of the same type and the effect would accumulate to the next player. For example, if someone plays a Draw 2 on you, you could play another Draw 2 and the next player would either have to draw 4 cards or play a Draw 2 as well. Likewise with Draw 4. Some times shock and horror would ensue as all 4 "Draw 4" cards would come out and some unlucky whelp (usually me) would have to draw 16 cards.
The next rule was what really increased the pace of the game. If someone played a card and I had the exact same card, color and number, I could play it out of turn and play would continue as if it had been my turn. Say play is going clockwise and the person on my left plays a Blue 4, if I have a Blue 4 and can play it before the next player, play would continue as if it had been my turn and the same player would need to go again effectively skipping the rest of the players at the table.
And last came the rule and leveled the playing field and could change the tide of the game in one fell swoop. If you have a 1, no matter the color, and can legally play it, when you do you have the option of trading hands with any other player. Usually this took the form of one player calling "UNO" and another player playing a 1 and trading their pile of cards with the other person's single card. Other times one players excitement of drawing some cool cards would turn into disappointment as another player traded hands with them. Sneaky players could sometimes bluff others into trading hands with them only to be disappointed with what they got.
Using just these three additional rules Uno became a wild game that would keep teenagers occupied late into the evening at the same time giving adults no chance to coast along. I personally wouldn't recommend trying these rules with small children as they tend to get confused and frustrated. But my older kids (9 and 11) really enjoy the challenge.