By "no roll or brim" I am assuming that you want some ribbing at the bottom, but not folded over...

Here is a simple ribbed hat. It doesn't have a brim (though the girl in the pictures has the bottom of it rolled up), and it will lay flat at the ends because of the ribbing. It's made with a bulky weight yarn, and you could just sub any type of merino for it (hopefully something in a much better color than they used here):

Here is a chullo ear flap hat. It's done in fair isle, but you can just use one solid yarn and ignore the chart work and knit all stitches throughout the pattern. It's got ear flaps and a tie, so it may be a nice one for what you're looking for:

Here's an extremely simple hat.

A pretty simple striped hat:

Another earflap hat:

There are some hats on knitty.com, but any of the male ones are for adults, so you will have to modify the pattern.

If you need any help with round knitting, you can pm me and I will send you some online tutorials.

"The Universe Molds Itself To Prove Your Beliefs"

http://knitty.com has free and reliable patterns. Most are sort of complex BUT I'm sure there are simple patterns for hats there too (search patterns and archives). There is also help from the designers and forums if you get stuck.

I have knit my dad simple, close-fitting chemo hats. I do a gauge swatch first to see how big I knit. Then I wing it. It works. I have also designed an excel file to help know how fast I want to reduce and if I want to make reductions in a sort of spiral pattern (so the hat looks smooth) or at every marker (so you can see the decreases).

Have you knit before?

"Macaroni - let me finish! - salad."

that's what I do. Knit around (using circular needles is easier~better still crochet)and gradually get smaller/bigger depending on where you started, then crochet, knit, or sew on ribbon ties.