Exodus3000 --Is a multi player RPG game which is set 1000 year in the future,you start with the 5000 mars dollars and when you have enough money you can exchange your mars dollars into real money.
You earn mars dollars by mining volcanoes, searching ruins and attacking other players
Exchange rate is 300,000 MD = $20.00.
Second Life -- Anshe Chungthe who is a SL property developer was recently announced the worlds first millionaire, with income earned entirely from virtual world profit, she has made $250 million Linden which can be exchange for $1 million dollars in the real world.but not everyone can make that kind of money. Second Life is a world of almost 2 million people where your avatar (your three dimensional character) can meet and chat with other people.
You can make money by buying and selling land (Virtual real estate), creating and selling content, clothing, gadgets, hosting and performing at events, Game shows, rock concerts and a whole bunch of different ways including sitting on camping chairs! Yes, store owners will pay you to for sitting on camping chairs near their store, because other people may come to hang out with you and the more people gather the better for the store owner, as it means some of those people may buy stuff from the store.
3-
PlayAndWin-- You can play many fun and entertaining games like Backgammon, Bingo and Mahjongat at PlayAndWin.co.uk for free. You can earn tokens, which can be used for drawings for the various Jackpots.
you can find the other game sites like these in the reference link i have provided,i hope you all enjoy some gaming and some money making opportunity,