I remember one very cold spell when we lived in Alabama.....power was down, we had no heat except in the Fireplace, so we all slept in the den that night....the next day, everything was shut down, stayed home from work, so we had to keep the fire going and to keep from being totally bored, we played Uno with the kids over and over till I couldn't stand Uno for many years after that.....I finally got over it.
Years ago I hitched a ride to London (after living in France a while) and when my original lodging plans for that night fell through, I met up with a couple of hippie types who happened along. We went back to their flat where we stayed up for hours playing a great English game they taught me called "Blackjack" -- which has no relation to our "21" Blackjack, just another game where the black jack is significant....
Fast forward to a few years later and I started to see a commercial card game modeled exactly after this English Blackjack game. The commercial game was called "Uno".
English Blackjack is still a better game as it has one element that Uno doesn't --- if one particular card is thrown, all players have to hand their entire hand to the next player. This means if you had dribbled down to two or three cards, you could suddenly be stuck with thirteen. Plus, everybody now knows what the player after them is holding.
Before Uno came out I spread English Blackjack (as we started calling it) around friends. It was a hit.
That added feature could be a lot of fun, too. I wonder whether something like that could be incorporated into our Uno play?
The thing is -- you don't need a prefab "Uno" deck to play the game; a standard set of cards does the same thing. You just assign the special cards.
As I remember it, red king reverses direction, twos are additive penalties, etc. The card that causes everybody to give up their hand, I don't remember but just pick one (e.g. black jack). Makes the game a lot more interesting and unpredictable. And for more than four people use a double deck.