Apple - Can Macs be put in hibernation voluntarily?

You could use DeepSleep.

I know this is a widget, but if you want an application, do the following :

1. Download the widget and uncompress the zip file containing it, but do not install it.

2. Right-click on the widget, the select Show Package Contents.

   

3. Copy the DeepSleep Application where you want.

   

Yes, of course you can. I myself use Deep Sleep widget (second link) to put my Macbook Pro into hibernation.

And if you prefer to use the command line, read this article.

There is a pref pane called smart sleep that is pretty good