Vocalix was a tech startup, aiming to "put voice on the web". I'll spare you the details, but I worked on it from 4am to 7am every day, mostly thanks to the wond'rous benefits of Modafinil, after which I would take a one hour nap and then go to work. I did that for 9 months straight. I wouldn't recommend it to anyone starting a startup. I made numerous mistakes, slips, mismanagements, bad technical choices, etc, because I was constantly exhausted, and because Modafinil affected my lateral thinking (though it's great for getting through a task list).
Vocalix was effectively dead on arrival, and within 3 months of me quitting my job we decided it wasn't going to work. Ouch.
My advice: if you're going to start a startup, do it properly. Reduce your costs, learn about startups and obvious mistakes, save up some money - all while still employed. Then when you're ready make the jump cleanly.
Some further thoughts about it here: http://swombat.com/2011/12/15/startup-escape-path