Beat the clock is a great section of the British Council site, which is part of their quizzes and games section and which I learnt about through David Deubel.
Here we can find lots of games about grammar, vocabulary, and everyday topics (tourism, schools, Christmas, means of transport). The games are on the short side and we get instant feedback, and they are suitable for students of all levels, although we have to explore the tens of games to find those suitable for us.