I know a guy who made a million dollars from it. A year after he got out, all his competitors were getting sued and shutdown. But he was off the radar, got to keep everything and never got in trouble. He found the niche, created the website in a few days, made money for a year or two, and shut it down with precision timing to maximize profits and minimize risk.
Another high risk option is becoming a vendor on Silk Road. Those guys are getting more orders than they can handle. Even the guys who just resell/repackage are making a killing.
You could even open your own Silk Road, which is lower risk than being a vendor. Just collect your small fee off every transaction, while staying completely anonymous.
Most of this stuff probably seems pretty shady to most people. But anyone with 10-20k, some balls and smarts can become a millionaire from it, very quickly.