Needle felting is probably the fastest, easiest and most satisfying wool craft there is. It also seems to be the one most attractive to the boys we know, perhaps due to the felting needle's resemblance to a tiny sword? All I know is my sons and their friends seem to particularly enjoy stabbing wool as a means of shaping it.
Some truly elaborate work is done with felting needles—do an image search on "needle felting" if you want to see a sampling—but it is also possible to get a perfectly sweet and simple shape in an hour or two, tea and singing breaks included.
C makes an ornament:
M works on a Christmas tree:
C and G work side by side:
S felting onigiri. All those blurry hands show needle felting motion as captured by my cell phone. (I'm old enough that it still amazes me to be able to use my little phone to take pictures and upload them to the web. How cool is that?)
And the partial results of that afternoon? J's spiral-adorned heart:
S's rice and sushi trio:
A Seussian Christmas tree:I'll add one caveat about this otherwise ideal winter craft: felting needles are barbed, and it is pretty easy to stab yourself—and it hurts! The pain from a felting needle lingers enough that all the boys mentioned it. It's thus not a great activity for the young or very inexperienced, but for everyone else, it's a truly fun and relaxing way to spend an afternoon.