lack of sleep causes:

I can't sleep very well anymore. When one is derived of sleep the world tends to shift in interesting ways. Or maybe it's just my particular senses or something.

Colors tend to dull. The clouding around my eyes makes colors a shade or two less. It's like messing up the tint of a tv dial: everything looks a little bit more washed out, like it faded through a washing machine or something.

Light. Light is much, much sharper. The sun gleams like daggers and casts it's horrible, horrible rays across everything outside. I try to stay inside as much as I can when I don't get enough sleep. I think it might just be psychological though; like, the sun is a process that reminds me of my lack of sleep, therefore, it drives me to go inside and sleep.

Music is a lot richer, if for the sole fact that it distracts my mind from sleep and keeps me awake. Try listening to your favorite CDs sleep deprived, it's cool. The sounds tend to make themselves more apparent when you're on the brink of collapse.

My brain races wildly, constantly thinking, simply because if I cease to think I'll go to sleep. And I can't really sleep right now.

However, because my brain is so active, it tends to fuel my paranoia as well. All of my interactions become much more frantic as my mind analyzes everything in seconds. Every minuscule gesture is something to find meaning in.

My fingers move faster, so typing is a breeze.

My eyes dart faster, so I read faster. Processing, however, is the eventual pratfall; I can't maintain everything in my long-term memory.

I sit more awkwardly. I hunch up even more than I thought possible. Craaaazy.