If you're using Gmail, the Boomerang extension will not only allow you to schedule messages to be sent sometime in the future, but you can ...

A boomerang carved from mammoth tusk The mammoth-tusk boomerang is about 72 centimeters long, gently curved, and shaped so that one end is slightly more rounded than the other.

Archaeologists at the time also unearthed a mammoth tusk boomerang estimated to date back to the same era. For nearly three decades, that specimen offered the tool’s oldest known example in Europe.