DeltaQuad suggested I tell the bots developers on this list about this tool, because he hadn't heard about it.
Max Semenik wrote a GUI tool to help newbies explore the MediaWiki API. It's called the API Query Sandbox. You can try it here:
https://en.wikipedia.org/wiki/Special:ApiSandbox
Please file bugs and enhancement requests in bugzilla.wikimedia.org (Product: MediaWiki extensions, Component: ApiSandbox). We want to make this better.
Thanks!
Sumana Harihareswara Engineering Community Manager Wikimedia Foundation