Entropia Universe and particularly Planet Calypso. I have been a resident for years. The sweat trade is a boondoggle. Sweating can bring it at most currently (7/17/10), $0.65 to $0.70 per hour. This is barely minimum wage in any country other than the poorest. The trick is to not sell to resellers. Leave the mining to others and the force nexus needed is bought at auction for $1.00 per 1000. With 1000 sweat gathered over 1 hour to 1 hour and half combine the two for $0.10 for 100,000 mind essence that can be sold for $1.60. Subtract out costs of force nexus, a $1.00 and cost of refining, $0.10. Then sweat acquired through the hard work of sweating for zero cost basis other than time. And get a $0.50 to $0.55 profit.
To further goose returns mine your own force nexus and spend around $10 to get back $7-$8 in force nexus and other raw materials. $7 worth of force nexus is 7000 force nexus with 7000 sweat can be combined for 100 mind essence per 1 force nexus or 700,000 mind essence. 7000 sweat over 6 hours is very doable. 700,000 mind essence can then be sold for tt value of $7 and markup value of 160% for $7 times 1.6 or $11.20. This is a profit of $1.20 or $0.20 per hour (6)of sweating and mining. By just buying force nexus pay 109% and collect all the money back for $11 spent (10,000 force nexus), 6 hours of sweat gathered, and 1,000,000 mind essence generated. Sell mind essence for $16 sale price. Subtract out costs of $10 force nexus, $0.10 refining costs for $11 rounded costs and $5 of profit. Then it's $0.83 per hour versus the $0.20 previously. A simple transaction obscured by numerous and repeated understatements of what's involved.
This $0.20 to $0.83 per hour is no where close to minimum wage in most countries. In fact the fears of chinese or other country gold farmers are overblown as the profits are so slight not even Grameen bank would lend to someone doing this work. But considering it is a game after all the return is attractive and doubtless will draw more players in to experience the success that is Entropia Universe.