Someone that racks up servers and equipment in a computer room. Usually rack monkeys form part of a team called "Infrastructure Team" or "Infrastructure Services."
Get the rack monkeys from the next door to put your new server in...
A rack of money is referring to a wad of cash. One rack is often of not always equil to one thousand dollars in cash. Typically in hundreds. Because it is a rack of money
When something is (or someone is acting) SO incredibly bizarre or abnormal that describing it as "being on crack" just isn't enough, it's said to be on monkeycrack. It usually has a very VERY high WTF? factor, and that is actually often the first reaction. The conclusion is monkeycrack must be cause.