An engaging game of cards

We have had a lot of success forming groups of children interested in playing Uno. It seems like most of the children already knew how to play the game but others have joined in who are just learning. The game involves matching color to color and/or number to number. There are wild cards, cards that say to switch directions, skip a player, take more cards from the pile, etc. The game involves following directions, taking turns, being patient, tolerating frustration, using strategy, and having fun. No gambling is involved!
If you know of any other good card games for children of this age, please let us know. It has really been great to find games that interest so many different children.