Just like the title says, what do you do that's odd? It can be anything, from what you do at home, school, outside, or when you're on the internet or playing games.
For example, I have this weird urge to open the doors for everyone for long periods of time. Or, in Assassin's Creed 2(this is REALLY weird, I think), where I just feel like I should bury the assassinated people; usually in the wagons of hay or in the sea. To pay my respects to them, to clean the streets(an achievement you get for doing, oddly), or just to be polite? I dunno.
Based on a Destructoid Article by Chad Concelmo- "Six completely irrational things I do in videogames"
http://www.destructoid.com/six-completely-irrational-things-i-do-in-videogames-181777.phtml