CoolThing! (tm) :))
Calc is really nice thing, I use it for a long time (several years).
It is perfect for casual use (as a replacement for traditional 'bc')
and for more sophisticated use.
And what is really nice - it is maintained again (since long time of
Test it - and you'll forget about 'bc' forever :))
An open, cross-platform journaling program.
A scientific plotting package.