How do you block light from windows?

Working out my first setup. Growing in a room with lots of space. Going to have to deal with light from windows when i get to flowering. Would like to not have to buy a grow tent since the room is only going to be used for growing. I'm also going to be needing to block off another section of the room for veg/clones. I heard black rubber sheeting was good. But I havent been able to find much when shopping. If anyone knows a good type, or even better where to get it that'd be great.

black plastic sometimes you need a few sheet to block out the lights, panda plastic is nice as its white on one side allready.
plywood is good.

Some people put rope lights in behind the cover to simulate the room being used

its really not a tough question

put up blinds,then plywood after
and caulk the angles

thanks for the info

panda plastic..

curtians? ,,

going to be going with the plywoof and panda film. Going to be growing right by the window. So i really need 100% light blocked.

visqueen or mylar works well.

1 sheet of mylar doesn't work for me, you need to have at least a few layers I think

I used a piece of tolex ( vinyl ) material from W-mart. Its got a white backing and I just put it around the window frame with a few tacks or pins. No light gets in or out and its easily reversable with no marks left. I think a 54" x 60" peice was less than $20.