**Source - This

24 Hour Mark

The consequences of sleep deprivation at 24 hours is comparable to the cognitive impairment of someone with a blood-alcohol content of 0.10 percent, according to a 2010 study in the International Journal of Occupational Medicine and Environmental Health.

36 Hours

Now your health begins to be at risk. High levels of inflammatory markers are in the bloodstream, said Cralle, which can eventually lead to cardiovascular disease and high blood pressure. Additionally, hormones are affected — your emotions can be all over the place.

48 Hours

After two days of no sleep the body begins compensating by shutting down for microsleeps, episodes that last from half a second to half a minute and are usually followed by a period of disorientation. “The person experiencing a microsleep falls asleep regardless of the activity they are engaged in,” she said. Microsleeps are similar to blackouts, and a person experiencing them is not consciously aware that they're occurring.

72 Hours

Expect significant deficits in concentration, motivation, perception, and other higher mental processes after many sleepless hours, Cralle said. “Even simple conversations can be a chore,” noted Kelley. This is when the mind is ripe for hallucinations. Kelley recalled a time he was on guard duty and repeatedly saw someone standing with a rifle in the woods, ready to sneak into camp. Upon closer inspection, he determined he was actually looking at a branch and shadows.

EDIT: Text added for the lazy :)