Shameless self-promotion... at my game studio we're making this Windows/Android cross-platform MMO (iOS coming soon):
https://play.google.com/store/apps/d...madotter.vhmmo
MMOs aren't really my genre of choice otherwise (I prefer single-player games) but I think we've succeeded reasonably well here by making more of a fully featured game for mobile rather than the very shallow mobile games seen elsewhere in the same genre.
In terms of other apps, I like
Feedly - it's one of the better RSS readers out there and has clients on Windows, Windows Phone, Android, iOS and the web - I used to use Opera's RSS reader but since the decline of that browser this is a neat replacement.