I never finished it, but this got me thinking again. I wanted to try PyGame, never doing any game programming before. However, I started on a lot of the logic around a game where a bunch of introverted employees in a company are forced to participate in some sport, specifically a football game, with robots 'encouraging' game play. The purpose is to stay far away from the ball while all other players chaotically run away from it too.
Last year, I spent an inordinate amount of time writing a Makefile and scripts to prevent re-runs when distributing files and configs to various VMs. I used it a little but there was a problem with it that I couldn't solve, so I gave up (and funny enough, I just wrote a tiny bash function to do all what I did before with that :D )
I wrote a tiny 'time-series' database in bash. It only supported two fields - probably something to fix. But, I wrote enough to query it and aggregate results into time ranges. I never used it for anything, but I was thinking of writing an nginx handler to call it to see page hits on my blog (the site generator which I also wrote myself, which is probably less useless, but not that useful with things like jekyll :)) I also wanted to play with C and what came out of it was something of a unit test tool that I based off of the Mac OS X version of assert() that prints out in a semi-TAP format. Useless because I don't usually write C code :D
I recently wrote a web scraper for a site with stuff I wanted to download and parse into some structure, but have no clue what to do with the data now that I have it :) So, it's in the status of useless at the moment.