One method I've used which puts some additional pressure on me to work on side projects is to write them out in the open in a public GitHub repo. Even though there's probably nobody following your development, the idea that anyone could be following along can provide some motivation to keep going.

Is your goal to learn go (or other language), or to accomplish a specific task (both valid and wonderful goals!)? The reason I ask because if it's the second, I've become dramatically more productive by really learning shell. Just as an example:

  comic_number=321;  curl -L http://xkcd.com/"$comic_number"/info.0.json | jq '{title, number: .num, title, date: "\(.day)-\(.month)-\(.year)", description: .alt, image: .img}'

That took maybe a minute for me to write, vs. like 20 or so minutes for Go. I personally can get stuck in a such a paralysis of doing things the "right" way in a "real" language. So, it's nice to be able to bang out a prototype super quickly and then iterate from there if I want.

edit: getting them all, because who can resist some fun code golf:

  yes | awk 'BEGIN{count=1} {print count++;}' | head -n 2311 | xargs -I {} curl -sL http://xkcd.com/"{}"/info.0.json | jq '{title, number: .num, title, date: "\(.day)-\(.month)-\(.year)", description: .alt, image: .img}'