Occasionally you've got to print a formal document, one that prevents you from re-using one-sided paper or printing in draft mode. But there's still a way to be more environmentally friendly: print the document double-sided. Even if you don't have a printer that automatically prints double-sided, there's an easy way to do it, and I'll tell you how.

Essentially all you do is print the odd pages of the document first then re-feed those pages into the printer and print the even pages. I'll talk about how to adjust those settings for two popular word processors.

I use Open Office Write. (If you don't know about Open Office, you owe it to yourself to check it out. Essentially, it's the Firefox of office software, and llike Firefox, it's free.) So here's what I do:
Bring up the print menu: Ctrl+P
If you need to, specify the page range. When doing this, don't try to parse the odd from the even pages; select all the pages in the range.
Click "Options. . ."
Under "Pages," select the odd pages by de-selecting "Left Pages." (I realize this may seem counter-intuitive.)
Click "OK" on the Printer Options menu and then "OK" on the Print menu.
Once the odd pages have printed, re-insert them into the printer face down with the tops of the pages the leading edge.
Bring up the print menu: Ctrl+P
If you need to, specify the page range. When doing this, don't try to parse the odd from the even pages; select all the pages in the range.
Click "Options. . ."
Under "Pages," select the odd pages by de-selecting "Right Pages."
Click "OK" on the Printer Options menu and then "OK" on the Print menu.

Microsoft Word works essentially the same way, but since I've had such a great experience with Open Office, I no longer have MS Office.

The nice thing about this method is that once you use it, your final document is collated in the correct order. You don't have flip through and reverse order of the pages.