Memorize.com

From site:  Memorize thousands of subjects.  Create things to memorize.  Share with friends and colleagues.  Good for studying for tests, preparing for class.  Older kids can learn by themselves, younger kids with the help of an adult.

Both memorizing and creating content to memorize are very fast. The format for creating pages is designed for speed and flexibility.

No sign up is required. Just go to memorize.com and click 'create page' and quickly create a page you can share with others.