The Humble Indie Bundle usually has all games available on all three major desktop OS'es as a matter of rule.

In addition to this, they are now offering a lot of other bundles as well, such as ebook bundles or bundles with games from a single developer. The latter often include Windows-only games.

I've noticed it's only the Humble Indie Bundles specifically that all the games have Linux versions. I've also noticed that they don't happen as often as they used to.

It's funny how it started as a kind of charity / publicity thing and switched over to being a store that runs slightly unusual promotions.

Well HB has decided to go for the quick buck by focusing on more bundles for Windows than anything else. Too bad they lost the multiplatform aspect in the way.

Really? What about the books and comics? I doubt that they are out to make a quick buck, since the sliders for developers, charity, and HB still exist on every bundle. I think they wanted to do this more often, so they had to broaden their lineup.