I often use auction games just before a test. It's good practice and I can choose any topic ( vocabulary,grammar,culture, etc.) we have seen in class.
Students make groups of 4 or 5 and each group is given 200 euros.I usually start with 10 euros and go up in fives.Each group chooses a spokesperson, who is the only person who can "buy" a sentence and give the answer.
I always read the sentences out loud so they can practise listening.Remember to bring a mallet!!!It will be more fun!!!