This is one of my favourite lessons. I made use of tracing paper to get learners to investigate the effect of 90 degree rotations and from there develop the rules for rotations around the origin.
The powerpoint walk you through the whole investigation and is followed by a worksheet, (with the answers already on the ppt) to reinforce the concepts. Make sure to read the comments I made in the notes section.
This lesson follows on lessons covering translations and reflections.