The new drawing objects in OpenOffice.org 2.0 are a lot of fun, and very useful, as well. (I've just shown some fun ones here.)
If you don't see them in Draw, Impress, or other programs, choose View > Toolbars > Drawing.
One nice feature they come with is a little yellow handle that lets you change their proportions.
All objects don't have this, but many do. Just grab the yellow handle and drag it.
Release, and the proportions change.
Here's how it looks with some other shapes.