Yes, I have an idea. Post a link to your site so I can see what css you would need.

http://www.periphel.de/isla/blog/index.php

It's an encyclopedia for an RPG, that's why there are a lot of sub-categories.

See how this works. Add this to the bottom of /skins/custom/custom.css

.bSideItem ul {
font-weight: bold;
font-size: 1.3em;
}
.bSideItem ul ul {
font-weight: normal;
font-size: 0.6em;
}

If you don't like the way that makes other parts of the sidebar look, then you can change .bSideItem to something else and make sure your category is labeled the same way.

That worked great, thank you! I tried to change the font color as well, but I guess this has to be done another way. (Actually, since there was font-weight and font-size I figured I could add some font-color, which, of course, didn't work... *g*)

It didn't work because they are links. You can change the color,

.bSideItem ul {
font-weight: bold;
font-size: 1.3em;
}
.bSideItem ul ul {
font-weight: normal;
font-size: 0.6em;
} 
.bSideItem ul a {
color: #FF0000;
}
.bSideItem ul ul a {
color: #569;
}

Perfect!! Thank you! :D