nodnarbo: but scrabble would be difficult because of different languages and dictionaries

Why? Technically, it isn't that difficult, most of the code will be language independent. The language stuff will be just a dictionary, and a mapping of letters to frequences and points. There may be some tricky policy decisions, for instance whether you're going to consider scrabble in language X a different variant from scrabble in language Y or not (and hence have separate ratings and tournaments), or whether the language played is like the number of points to play to in a backgammon match (which is all lumped together in ratings).

That is, if you are going to make scrabble versions for all languages. But many languages only have a handful of active people. One could just recognize that English is the most wildly used language here (by a large margin) and just offer scrabble (or a similar game) in English. And yes, it would be unfair for the person who only speaks Tiki-Tiki, he wouldn't be able to play. But he won't be able to play if the game isn't there, so it's hardly a loss.