Onirim has just appeared as an app
Pretty cool solitaire card game, one of Zee Garcia's favorites

I wouldn't mind a good online 4-player spades or hearts game.

anyone got a GOAT tower defense game?

also, these are some of my favorite time killing games for a desktop and i think you can download them to your phone:
http://www.windowsgames.co.uk/

The slay game in particular is one of my favorites

(hopefully allowed to add link. sorry if not)

I think the Lords of Waterdeep app is pretty good. AI is decent and has different degrees of difficulty. There's also multiplayer I believe. Online connectivity not required to play, and no ads because you buy the app.

I play the tichu app a lot

Freitag (Friday)
This is a port of the card game, a single player deck building game that costs €3.99. Basically, you never want to buy the real card game, because the app is soooo much easier to play: you don't have to remember things or shuffle cards etc.

The game is a single player deck building game with Robinson Crusoe theme. Robinson is useless at the start of the game, represented by a rather bad fighting deck. Fortunately he has 20 life points, which is valuable resource.

I can really recommend this game. It has a rather steep learning curve. In the first games you will be clueless and lose quickly. If you win a game in your first 10 attempts you are a smart feller.

Every round you get to choose between two cards that you will face with your deck. Each round ends with two possible results: either you win and you add that card to your deck or you lose and pay life points to thin out bad cards you drew from your deck. In either case, your deck gets better.

Your deck will improve and in the end you need to face two very big pirates. Beat both of them and the game is in the bag.

Just continue playing, learn what exactly the abilities are of your fighting cards, how they interact and which combo's are possible. You will end up winning the game and trying the higher difficulty levels.