Wave Rider is a fun game for students to practice writing sinusoidal graphs. The direct link is http://www.bbc.co.uk/bitesize/higher/games/wave_rider/
More activities for transformations with sine and cosine graphs can be found in the Math 30-1 Demonstration Course resources.
http://learning.arpdc.ab.ca/mod/book/view.php?id=4375&chapterid=205