I used to build Linux router software that would fit on a floppy disk and run it in a 486DX2, for absolutely no reason except it was fun as hell. Made a nice web UI, packed in a ton of advanced features. Wanted to try and start a company to sell little open source routers, but then I found out cheap routers were quite hard to make money on, so I became a sysadmin instead and mostly browsed Slashdot for 10 years. My big regret is not becoming a musician or woodworker instead.