When most people think of felting their knits, they probably think of throwing them in a top-loading washing machine (you may have discovered the term "felting" when you or someone else did this unintentionally!).
In fact, some people will say that the only way to felt by machine is with a top-loader (it's still possible, but a little more difficult, with a front-loader, which we'll talk more about tomorrow). It is certainly the quickest and easiest method for felting a whole range of knitting projects, and it's just about the only way to go when felting really big projects that wouldn't fit in you sink. (You can felt in the bathtub, but it would take forever and be difficult to keep the felting even across a large project.)
Using a top-loader is great because you can keep the lid open and see a little bit of what's going on (or turn it off and peek in if your machine won't run when it's open), and it's super-simple to turn the knob back and let the machine agitate longer if you need it to -- a trick that can't be accomplished as far as I know with a front-loader.
I was certainly glad I still had my top-loader when I was doing my felting book and had to felt a giant alpaca baby blanket! What's the biggest project you've ever felted? I'd love to hear about it!