It�s great to have the chance to "talk" to so many people with such great ideas!
you can also use dices to practise Going to : You build a dice with the personal pronouns; and another one with different verbs in the infinitive form. Students must throw the dices at the same time and build correct sentences with the information given. They also need to complete those sentences so they can make some sense,it makes them practise vocabulary,too. This activity is great, because you can use it with any verb tense you like!
I�ve also made a different activity which was divided in two classes. In the first class the students made a travel plan with some suggestions. For example: 10 0�clock- visit the Buckingham Palace. This made them curious and looking forward for the next class. So, the next day I�ve arranged the classroom as if it was a bus and we were all travelling through London! I�ve used slides with pictures of London and as I was showing them, students were building sentences using Going to. For example:It�s 10 o�clock! What are we going to do now? We are going to visit the Buckingham Palace.
I hope my ideas are useful. They have worked for me...