In addition to the good suggestions for others in this thread (like setting it up as a portable gaming device or a server of sorts), it could also be set up as a low-distraction productivity machine. I don't know how well something like LibreOffice would run on it, but I imagine you could probably use a simpler word processor or even a plain text editor.
Worst comes to worst, I wonder what hardware support for this thing is in something like ReactOS or FreeDOS.
It isn’t an OS. It’s a set of DLLs to allow Unix applications to be compiled and run on Windows.