sci.crypt has fun stuff from time to time, if you like cryptography topics. comp.lang.c is also nice, if you filter off-topic posters. They also recently start

sci.crypt has fun stuff from time to time, if you like cryptography topics. comp.lang.c is also nice, if you filter off-topic posters. They also recently started a usenet newsgroup for the Gemini protocol, but it's not widely known yet.