This is a side project of mine inspired by Soulver: http://www.acqualia.com/soulver/
It's pretty basic at the moment but is useful as an alternative to a calculator app, and as a way to share calculations online, e.g. here's a little SaaS monthly revenue calculator: http://notepadcalculator.com/s/ba8c945e65a6816f63b253272b7c9...
Interested to see if others find this useful. Criticism welcome!