When I am bored I just play some Counter Strike to relax and have some fun killing dummies, however I also like playing some GTA San Andreas MultiPlayer and Dota 2 as well.
Well.. this is the "Mobile Game" section so those games don't fall in the category, but it doesn't really matter as long as we chat! Do you play CS:GO or classic 1.6?
I honestly still have a 3210 Nokia phone, the one with the Snake game and Space Impact. Say what you will about these newer games, those two games have stood the test of time and can still be a perfect time waster right now. Space Impact and Snake have really great gameplay and replay value, so people of all ages can still appreciate the simplicity of these pixelated games.
I'm currently playing Dungeon Hunter 5 and Summoners War whenever I have some spare time to use my phone, though they're very battery consuming so it can get annoying if you want to have your phone charged throughout most of the day or need it to be that way. The games themselves are a lot of fun if you're into RPGs and Diablo like play.