Is the spare Infinite Improbability Drive important?
Answers:
1. Read the Guide entry on Improbability Physics.
2. You'll need the atomic vector plotter from the Vogon Hold. If you never got it while you were aboard the Vogon ship, you'll have to start the game over or go back to a saved position.
3. You'll also need a good source of Brownian Motion.
4. Consult the Hitchhiker's Guide about Brownian Motion.
5. Have you seen any hot liquids?
6. You'll need the cup of Advanced Tea Substitute (ATS), which you can get from the Nutrimat in the Galley.