I love to take photographs of the sky and its reflection in the sea or other water. The amount of different colours you can see in the sky at various points of the day amazes me, which is why I end up with numerous photographs of it in different locations.
Unfortunately you can never quite capture the full beauty of the sky with photography as the eye sees differently to the way the photograph often ends up, but with practice (and maybe a little help from Photoshop) you can learn to get it pretty close.