Flippity

Flippity.net is a free website that allows you to create flashcards and games, including a memory matching game (similar to Concentration), a Jeopardy-style quiz show, a board game, nonviolent "hangman" style spelling games (a melting snowman, apples on a tree, etc), Madlibs, and others.  

(See here for using Flippity flashcards as a tool to encourage learner independence.)

You can also use Flippity to create games and activities to be done in person (Bingo, wordsearch, crossword, and anagrams).  A few pointers on making Flippity games are here.

Pros:  Free, minimal ads, and you don't need an account to use the tools (no personal information)

Cons: It's somewhat clunky to add images, and only flashcards include (machine-generated) audio.