Hi,
as a warm up I often use a small exercise on a whiteboard (or blackboard) as I find the young ones really love using the �big board � and it �s quite informal :
1 - draw pictures of the vocabulary you want to revise / use and say the word - the children have to draw a circle around the picture or tick it - with the little ones it works well for the letters of the alphabet or numbers / shapes etc.
2. pictures and words as a matching exercise - with each child taking a turn to match one up
A great one for body parts and shapes is on a pinboard - we called it make an alien:
Make some templates from card for the body parts you want to teach/revise make them a little bit unusual like a square head , extra long legs or very short, lots of eyes etc
The body is already in place (I just did a medium sized oval shape)
The first child places one part at your instruction for example - Put the triangle head on then that child tells the next one what to do and so on until they create an unusual alien with ears on their legs and all sort of fun things
Sometimes we reinforced this by drawing our alien and labelling the parts - we also did an extra large one for a wall display
Another one my children loved was musical chairs with the vocabulary or pictures stuck onto the chairs and a bit of music to dance around to - I often used this to end the lesson as well to reinforce new vocabulary - you need a bit of space for this exercise and it depends of course on the size of your class.
I agree with Cemorana that the young ones really won �t engage in full english conversation but will use vocabulary they learn with encouragement and as their confidence grows.
Hope this helps