Thanks go out to LifeHacker for pointing out this special offer:
Go download the full version of ConceptDraw MindMap 5 (normally $200), then fill out a simple registration form and get the license key. The license key turns the demo download into a full version copy. Grab this one up before time runs out!
You can download either the Windows or Mac version.
I am enjoying testing out the mindmapping and brainstorming features. Let me know what you think of it in the comments.