The distribution calculator is a great tool for teaching and to look up certain quantiles. Other tools (e.g. 'Confidence Interval for One Proportion' or 'Sample Size for Confidence Intervals') are also a great help, but they're hidden away under the Help -> Sample Data -> Teaching Scripts / Calculators menus.
I would love it if they were more easily accessible.
There are add-ins available with these contents, but they don't always work as reliable as when going through Help -> Sample Data -> ...