What steps will reproduce the problem?
1. Go to http://golang.org/pkg/time/#example_Sleep
2. Click the run button for the Sleep example.
3. It panics with a message saying "No sleeping in the playground"

What is the expected output? What do you see instead?

The expected output would be the program finishing after the sleep time. Instead I see
the panic message.

I understand this is not an easy bug to fix, just filing it for reference. Or maybe we
could remove the Run button for any example using time.Sleep?