Star Trek: Starship Creator is a computer-based vehicle simulation game released by Simon and Schuster Interactive in 1998, as a spin-off of the Star Trek franchise.
The game allows the user to create their own starships, crew it with personnel from the Star Trek universe, and send it on a mission to evaluate its performance. The program was designed with input from Michael Okuda, Denise Okuda, Rick Sternbach, and Doug Drexler, who were responsible for many of the technical or reference-oriented books produced for Trek.
Source: Wikipedia, "Starship Creator", available under the CC-BY-SA License.
The 'game' portion consists of sending your creation out on randomly generated missions, and seeing how they do. However, the real focus is just playing around with a Star Trek-themed spaceship design system.