Winning Words is a series of free iPad apps that feature matching / “memory” style vocabulary games. There are six apps in the series. Each app is played in the same manner of flipping a card and trying to find a match for it. The six apps are synonym match, antonym match, homophone match, compound match, double letter match, and singular/plural match. Each app supports up to four players and has three levels of difficulty.
I tried Winning Words Synonym Match to get a sense of how the apps worked in practice. The app did not require me to register or enter any information, I simply opened it and started playing. The app is appropriate for elementary school and middle school students.