For a fun project; rejuvenating a 1978 Chess Engine https://github.com/billforsternz/zargon. It's the second time I've worked on the same engine. The first time I got it working nicely on modern machines, running four orders of magnitude faster than in in 1978. This time I hope to get it running much faster than that. I found a bug in the 1978 Z80 assembly the other day. A blog post "Fixing a 50 year old bug..." or similar suggests itself.