Free PC Addictive Game

Hey Friends,
Plz suggest me a good addictive PC game that is free I have tried Battlefield 3 and Dota 2 but couldnt stick to any of them I spend all of my money on BF 3 so now I want a free game whether on Origin Uplay or Steam but should be really addictive.I will be happy if you helped me.
thanX in adVance

If you're open to MOBA's, Smite and Heroes of the Storm are a bit addicting (and less punishing that Dota 2).

I've been playing Blacklight: Retribution for 3 years, I think that counts as addictive :). They announced a major patch for July 29, hopefully they won't pospone it. AFAIK they're gonna change the launcher and everything, meaning we'll have to download the whole game again. Just something you should know if you have a slow internet connection.

This. Try Heroes of the Storm. HotS is great fun.