The Unquiet Slumbers of the Apollo Moonwalkers
americaspace.com
americaspace.com
Or use a Sensory deprivation tank, you can get access to them commercially. You can even use a heater and a bathtub to makeshift one.
The experience reported by these astronauts is that of the pressure underneath them being less. I can think of no way to simulate this on earth, save napping in near-freefall (e.g. while parachuting, or while on the Vomit Comet). This does not strike me as a sound idea.
Apparently he once saved one of the big quarterly billing runs from disaster.