I've been teaching classes for a while, and have come across a lot of great resources. One of the sites to which I consistently return is www.businessballs.com. Yes, it's an odd name, but it provides an astonishing array of information. One of the best things about it is that you can use these resources as at no cost long as you attribute the site.
Here are some examples. I encourage you to explore others for yourself:
Can you fit your entire body through a business card? It's possible, and the answer is available here.
A parent has two children. One of them is a boy. What is the probability that the other child is a girl?
It's 1 in 3, or 33%, of course.
Don't believe me? Check out the explanation here.
You can also find tips and techniques on business theory, brainstorming exercises, and a community of peers with which to exchange ideas.
Hope that this helps add to your toolkit!