"Warm up routines" before starting a game?

I've heard some folks talk about "warm up routines" before they begin a game here on chess.com, like studying a chess book for 30 minutes or doing tactical puzzles, in order to "get their mind tuned in". I'm curious what you all have to say on the topic. Do you do anything to prepare, or just make sure you have a cup of coffee at hand and go at it?

I like to watch some chess video's on youtube or chess dvd's to give me that chess feeling, sometimes a couple of matches against the computer before I start up playing chess on this site.

Not using a computer period, or not using your computer for chess related things?

It makes sense... Perhaps the computer stuff serves more as a distraction before an OTB event.

i do mental calculation for 10-15 minutes.

It is not that chess is a sport. 

OTB, you have plenty of time to get into the game. Hence, the only thing I do is make sure I do not play my opening moves too quickly. Besides, I would rather socialise before the game.

Playing Blitz on chess.com. You can play so many games in a short period of time that is easy to improve your rating after a poor start.