Cool, but it's now impossible to submit anything, as the server is being DDOS'd. Not out of malice, mind you, there are just too many geeks out there, and this is a Sunday...

Still, one can read the titles of the already posted rooms with:

env URL=https://incredible.xkcd.com \
curl -SsL $URL/machine/current \
| jq .grid[][] | grep -v '^null$' | tr -d '"' \
| while read uuid; do printf '%s: ' "$uuid"; \
curl -SsL $URL/folio/$uuid \
| jq .blueprint.title; done

(Useful to find out if your room made it to the public set)