[synth3tk]

On the "challenges" page, you may want to use lower-resolution images. Even with my 3Mbps DSL, I watched the images load from the top down.

The black text on red background almost gives me a headache, along with the link color on red, but this may be personal preference. This might also be attributed to the font-family, too, but I can't be sure. I would try change the content container's background color and/or changing the text color.