Vocabulary building is of course one of the most essential parts of learning any language. The old-fashioned way of just learning lists of new words is certainly passé. All interactive games should be encouraged in the classroom although this is very difficult to instigate in Thailand.
The very best way to learn vocab is through context, and this is where games come into force. The use of dictionaries is also essential, as well as teaching students how to use them correctly to avoid choosing the wrong definition.
An excellent dictionary software is the Ultralinua dictionary
which includes hundreds of examples of language in use for many language pairs. It also has an interesting flashcard feature.