www.freerice.com is a webpage run by the United Nations World Food Program.
Choosing from a wide range of topics such as Art, Chemistry, Geography, Maths and Languages you can try and find the correct answer to a number of questions. The important thing is that for each answer you get right, they donate 10 grains of rice through the UNWFP.
In the Languages Section, the questions about French, German, Italian and Spanish are mainly Vocabulary questions but if you click on English you get two choices: Grammar and Vocabulary.
Choose a topic and give it a try!