I have little experience in running a business and I definitely don't want to deal with major competition, that every legit business has that makes good money.
One of the only alternatives would be crime, but that's handled by *insert whatever nationality currently* mafia and I have no intention of spending a day in jail or buried in a ditch.
Now the third is the grey area. Not illegal, but not exactly honorable. Big bucks, questionable business practices, but noone will really bother you other than maybe calling you a scumbag. For example: jewellery sellers on tv or mediums on late night TV. That sort of thing. Really, anything goes that isn't prostitution, drugs, hitter for hire or any of that stupid illegal shit. Gambling may be the only exception, but what kind? I also thought about porn, but the internet has so much of it it's impossible to find an unfulfilled niche. Any more ideas?