That one game you didn't want until you played it, then wanted the hell out of it.

[PixelXenoKing]

Borderlands 2 for me its a little different I already started playing it when it first came out I got to around level 17-20 than stopped. After 4 months I started the game up again then suddenly I was playing and paying for everything in the game.

[Cheshireson]

A bit of a time gap for this one...

I originally got Portal for PC back in the summer of 2011 when it became free to download on Steam for a limited time only. I got to maybe the first test chamber and then I just... stopped playing it. I purchased The Orange Box for the Xbox 360 some time early this year. I played through all of Half-Life 2 (including Episode One and Two) first and enjoyed it a lot. It took me about five months to complete it all though - playing it intermittently of course.

After that, I decided to start a playthrough of Portal again just a few weeks ago and I ended up finishing it in nearly one play session. It's short, but sweet. Also, GLaDOS has exceptional character development and I quite like the little quips and comedic dialogue she provides throughout the game. It kept me interested, and now I can see how the series has conjured up such a cult following.

Also, I bought Portal 2 the other day and I was so immersed in the gameplay that I have nearly finished the game already!