The only way i've been able to consistently win risk free is by using casino bonuses and playing basic strategy blackjack. I've seen a few sites punting this idea. This site is pretty good http://www.3money4u.co.uk but there are others out there (all very similar i'll post them if anyone's interested)
Basic idea is that you deposit $200 and the casino matches it so you've got $400. You then have to wager a certain amount usually bonus x 10 = $2000. If you play basic strategy blackjack the estimated house odds are around 0.5% (depending on house rules)
2000 x (0.5/100) =10 is the expected loss!
Means you walk away with $190 for an hours work. You can repeat this with bonuses monthly - nice little earner and RISK FREE. Apologies if this idea already been posted or everyone knows about it. I'm sure most of you do.