The last couple of months I've lost myself to Puzzle Strike, a quirky deckbuilding game in the vein of Dominion/Ascension. What I never liked much about most deckbuilding games is that they weren't very interactive and that the players were symmetrical.
Puzzle Strike is like a mix of Street Fighter, Starcraft, Dominion and Tetris. At first I was taken aback by all the cards (chips), but after three games I started getting the hang of it and could already feel it was better than Magic: The Gathering, which I have loved playing for since it came out, twenty years ago. Seriously, I can't play MtG anymore without thinking I wish I was playing Puzzle Strike.
What I like so much about it is choosing a character and getting really good at him/her. There's so much depth. After half a year, I feel like I've only seen a fifth of everything I know I can explore to improve myself. And there's probably more.
It's also a board game, but you can play it for free (two characters are allowed to be played every week) here : http://www.fantasystrike.com/game/index.php
It doesn't work on Android/iOS, but does work in Windows Browsers and Safari on a Mac (as far as I know)
Just letting you guys know there's an awesome game out there to delve into, for free. And although there is a healthy amount of (friendly) players online most of the time, I wouldn't mind having more people joining online tournaments. Hence the tip.