UPDATE: Well, the first few days I ran this test I was able to view it on systems that weren't logged into the Google Wave developer sandbox. However, now it seems as if you can't view (never mind interact with) a Wave unless you are logged into the sandbox.
I'm currently working on a review of Google Wave, trying out some of the API and developer oriented features. One of the capabilities is the ability to embed a Wave into another web site. Several of the Waves I attempted to embed failed but this one worked.
In this Wave, I'm also using a Wave robot, which has the ability to provide feedback based on other information in the Wave.
This Wave is a standard Magic 8 Ball, which responds to basic questions. Clearly, it knows its baseball.