In case you missed it, tangrs has been working hard for the past few months to get Linux ported to the TI-Nspire calculator.
The port is not yet fully stabilized nor quite ready for broad consumption and requires some user-level knowledge of Linux systems, but is definitely worth a try. It basically looks like a Ndless-based TI-Nspire specific loader configured to run a Linux kernel image with a RAM disk .
Experimental support for root filesystem installed on USB mass storage is being worked on, so that Datalight’s proprietary Flash FX/Reliance filesystem used by TI’s OS isn’t a limit anymore. This also means that the native TI-Nspire OS image is not replaced by the Linux system, and Linux can been booted on demand.
Support for USB keyboard, X server, directFB, Wi-Fi (with the help of a powered USB hub) and text-based Internet browsing is progressively being added and tested (thanks to Vogtinator for the build and demo).
Linux for the TI-Nspire also means instant compatibility with hundreds programs (although cross-compilation to ARM is necessary), including command line tools, script engines, mathematical and scientific utilities and games, as long as the constrained RAM size and CPU speed are not an issue for them.
The project is under active development, tangrs is looking for contributors to make Linux become a strong alternative to the stock OS.