Embdedded Linux appeals to the hobbyist in all of us, but getting things going can be tedious and drawn out. Between cross-compiling, filesystem population, packaging, and preparing a custom Linux .config, one can quickly exhausts their quota of "free-time" before making much headway.
For the Yocto Project 0.9 Launch, we put together a UPnP Media Network running across four architectures in relatively short order. The poky build system's concept of layers enabled us to reuse all the base recipes (for the kernel, base system, and the boot image creation) and focus on adding the necessary pieces.
Have a look for yourself and see what you can build in your "copious" free time! http://yoctoproject.org