In DragonVale for the iPhone and iPad, there are three limited dragons only available during the Olympics called the Olympus Dragons.
The three dragons are naturally called the Gold Olympus Dragon, the Silver Olympus Dragon, and the Bronze Olympus Dragon.
The recipe for all three of these seem to be the same, requiring an Air hybrid to mix with a Lightning hybrid.
For example, some combinations are Blazing + Crystal, Fog + Storm, Willow + Quake, Blazing + Storm.
Check out my DragonVale Breeding Guide for more dragon breeding combinations as well as other Air and Lightning hybrid combinations you can use to get your Olympic Dragon.