In 1979 my family bought our first real computer, an Apple ][+. As much as I loved that one, I might have loved this computer even more.
I still remember the set it came with, 452 Mobile Tracking Station. A little gray space truck and trailer with one minifig astronaut.
I found this at my parents’ house last month while building Legos with my daughters. 30-something years later, and it still works perfectly.