The Rappture toolkit provides the basic infrastructure for a large class of scientific applications, letting scientists focus on their core algorithm when developing new simulators. Here's a demo of a Rappture interface for a Matlab script which simulates conduction through a molecule. This interface was generated automatically by Rappture, based on a description of the tool inputs and outputs. Rappture also makes it easy to put a friendly, interactive interface on existing legacy applications, without having to rewrite the code. For example, the SPICE circuit simulator has been around since 1972. You can now run SPICE on the nanoHUB via a simple Rappture interface. This shows the power of taking a powerful, batch-processing tool, and making it more interactive and accessible.