Among their achievements: adding new features, creating new operating systems, connecting the calculator to keyboards and other hardware, playing a video excerpt from "The Matrix," and even running Nintendo Game Boy video games. Not bad for calculators such as the $100 TI-83 Plus, introduced in 1999 with a Z80 processor running at 6MHz, 24KB of memory, 160KB of flash memory, and a 96x64 pixel display.

Why all this work for projects that realistically are not going to reshape the future of computing? Much of the motivation parallels mountaineer George Mallory's rationale for climbing Mount Everest: "Because it's there."