I love Moose. It's a postmodern object system for Perl 5. It's very powerful, saves me writing a lot of code and is very extensible. Dave Rolsky received a grant to write the Moose::Manual and it's a great introduction to Moose, how to use Moose and covers every part of it in detail. I don't really enjoying reading documentation on a screen, so I converted the manual from Pod to LaTeX so that the typography would be beautiful, fixed a few typos in the manual, designed a nice cover and you can now buy a copy for yourself. At the YAPC::Europe 2009 auction a copy of the book signed by Yuval Kogman and Larry Wall went for €120!