MathCad & S Plus (Mathsoft)
This company produces two products that might interest
economists -- MathCad and S Plus. The former turns your computer
into a "live worksheet" where you can perform numerous types of
calculations. The latter is an object-oriented statistical analysis
program. It has a large following in the statistics community.
Extensive information on both of these programs can be found here.
http://www.mathsoft.com/