Combining technological advances with German online games can make learning especially fun for your students. These are also great homework assignments, as some students may feel more like it is "play" than "work." You're accomplishing several important goals when you use online German games.
Alternatively, you can seat students in small groups in your classroom, library or computer lab. This option depends on your school's computing facilities and usage policies.
Quia.com is just one provider of numerous German lesson games, especially concerning vocabulary and grammar. You and your students might especially want to check out options such as "Conjugate the verb sollen" or "Working with waren." If your students are learning more basic German, you can select from plenty of alternatives such as those dealing with numbers and colors.
A previous Bright Hub article, How to Find Free Internet German Grammar Games, may also prove helpful in giving you a number of language learning gaming options.