Quak Quak

I came across Quak Media via a Google image search and was particularly impressed with these two pieces. The vector illustration I like purely because of the use of colours and attractive swirls but the H2O advertisement is really quite clever. As the mouse cursor goes over the banner, it creates an effect not dissimilar to when you run your fingers/hand through water. Its made me really quite intrigued as to how you might code this...