Real estate - I used to own two flats, and get $200-$300 from each one of them. I recently sold one though - I think I can make a better use of the money by other means.
iPhone/iPad apps - I did two or three successful apps, right now they bring in $20-$40 daily. The last time I touched/promoted any one of them was last December, and the sales are quite steady now.
I bought some S.DICE shares ( http://polimedia.us/bitcoin/mpex.php?mpsic=S.DICE ) @0.0032, spent 800 BTC on them I think. Got ~20BTC from dividends first month, ~5BTC dividends the second. It's very risky, but there is some potential for growth there.
All in all I get ~1200 USD of passive income which would be considered an average pay in Poland. I've got a startup on top of that which brings a lot more though.