(I'm lucky enough to have a shared one at work I can mess around with, so I've been playing with that occasionally, like cutting some mutant Penrose tiles. I've never used Inkscape before so that's definitely a learning curve, with new challenges like "a line on top of a line is different than a single line."

Metal would be fun. I'd also be thrilled by metal 3D printing, but even nice plastic... the printers in the shop are kind of disillusioning -- they're the kind that builds out of plastic string, basically a scanning hot-glue gun.)