What can 250,000 people do in their spare time to earn money?

Educate them. They should get their next highest degree that prepares them to do more and follow their individual interests. I'm jumping in because I've done some work with domestic workers from the Philllippines in particular (and if they're migrant workers the OP is referring to) the majority of these ladies are literate college graduates, one in particular had a Master's Degree. Education is not helping in some of these countries where there are no jobs to be had.

I'm guessing that the majority of them, if they follow the pattern of domestic help here in Singapore, have mobile phones and text plans that allow them to stay in touch with their family. There's work on text based income earning opportunities - http://txteagle.com/. And ahttp://www.technologyreview.com/business/21983/?a=f from MIT's Technology Review: Now Nathan Eagle, a research fellow at the Santa Fe Institute, in New Mexico, is launching a project similar to Amazon's Mechanical Turk but that distributes tasks via cell phones. The goal of his project, called txteagle, is to leverage an underused work force in some of the poorest parts of the world. Eagle says that distributing questions to participants in such developing countries via text messages or audio clips could make certain tasks more economical, such as the translation of documents into other languages, or rating the local relevance of search results. It could also provide a welcome source of income for those involved. "We're trying to . . . tap into a group of people to complete these tasks who haven't been tapped before," says Eagle. "And we're using mobile phones, which have a high penetration rate. More people are mobile-phone subscribers in developing countries than in the developing world, so we can get a user base of billions of people." If it doesn't suit your own location, then perhaps given the large number of people you'd to help, perhaps something similar can be set up for them/with them?

Seconding the sewing/piecework recommendation upthread. I've been thinking lately that with the current popularity of vintage clothing, there's a viable business model for the taking for whoever can get a good vintage repro service up and running. Like, I send you my beloved but fragile 1950s dress, you copy it and send the new dress back to me with the original. Or you take vintage patterns and make them in a range of modern sizes. There's at least one eBay seller I know of who does that successfully.

Have them start their own bank.

Teaching Spanish linked to this askme http://ask.metafilter.com/196581/Existe-esto with an realtime human app ... :)

you notice your maid is spending 20 hours a week moonlighting on a separate project while collecting a paycheck from you and living in your house, Eh. I've never had a maid and surely never will, but one of the worst things about having a maid must be having her underfoot all the time when you wish you had the place to yourself. If she could clean everything I wanted her to clean in even less time and then get out of my way, I wouldn't give a damn if she spent the rest of her time quietly raising sea monkeys for fun and profit.

Education is not helping in some of these countries where there are no jobs to be had. QFT. Even first world countries are finding out that throwing a college degree at a problem doesn't make it go away. More graduates does not automatically equal more graduate jobs.

Really 250,000? If only ten percent of them are really smart, that's 25,000 really smart people stuck sweeping floors and cleaning toilets who could instead learn how to do just about anything you throw at them. Give those 25,000 really smart people something mentally challenging (compared to what they're doing) that also pays well and they will run with it. Programming? Get someone to provide basic computers or phones they can use in their downtime to learn Java. Is it possible to program on (not just for, but directly on) a smartphone, maybe by adding a proper keyboard so you don't have to type everything on a tiny phone screen? They could use the same phones to provide part-time telephone support for existing products. Maybe the phone manufacturer could provide the phones as part of an experiment to see how this goes. So, for example, they start by offering phone support for certain Android phones (or some other products), meanwhile learning how to program for those Android phones, and then they sell their services as Android/Java programmers to the phone manufacturers or start their own software companies. 3. ??? 4. Profit! No, I think something like that might actually be possible. With a lot of luck and backing.

If they have computer access, get them to do https://www.mturk.com/mturk/welcome. It's not exactly a career or a future (or a lot of money), but it's a way to make small amounts of extra cash. And unlike most things you can do it in tiny little bits in whatever odd time there is, without training.