How do I make those grass skirts I've seen on the round cakes? I've though about just using a knife and cutting the lines but I'd want them to look all even. Has anyone ever done this before?

I am not sure specifically what cakes you've seen that you want to replicate but if I were doing a grass skirt on a cake I would probably try using the grass tip. If that makes smaller "grass" than what you are looking for, you could do a larger round tip but it might be tedious. Good luck!

I did mine with buttercream and the grass tip. I should have started on the back of the cake because I got better as I went around. As you can see, I didn't do such a great job on the front.
http://cakecentral.com/gallery/1727082/luau-at-the-beach

Tip 18 was used to make the grass skirt on this cake. http://www.flickr.com/photos/42607550@N00/6118137558/in/set-72157625779795603