Calculators (and related mental activities) as hobby or as avocation?

[pier4r]

Yes passatempo is one of the suggested words by wordreference.com . Passatempo captures exactly the "hobby" part of "nice to have, but not important". It is like "leisure activity to let the time pass somehow".

What I meant instead is that I wish to have more time for the hp50g and related activities. Another word to describe this may be "passion" but it does not cut it properly.