Earlier quoted context omitted.
Easy - study children in Eastern Europe/Baltic states. Lots of people grow up bilingual, with English as a third language, too.
Lots of those people become tetralingual because they have time left over the three languages that are taught anyways. E.g. Russian and Estonian as native language, English plus a fourth language from school. Those who do not have a bilingual family only learn three during the same time. E.g. Estonian, English and Russian. I kind-of envy the first group of people because it's cool to be able to access so many spheres…
Russian forums have all sorts of nice software/hacks for smartphones, tablets, laptops, etc. Only place I could find a programmer (and a ton of firmware) for washing machine and dryer boards.
Chinese forums/websites seem to be even better, but harder to get into (translation issues, have to sign up/log in to a lot of them).