When you're a computer geek, you really should be proud and proclaim it to the world.
Almost everyone carries a calculator (check out your cell phone).
Having an RPN calculator shows low level geekdom.
Having a calculator watch shows moderate level geekdom.
Having a calculator you built yourself shows high level geekdom.
Having a RPN calculator watch that you built yourself will make all other geeks bow down before you (with the possible exception of those few who built a nixie tube watch).