DNS over SMS
A text-message exchange used as a transport for DNS queries and replies.
DNS packets can be represented in a short-message workflow. The resulting exchange is slow and constrained, but it demonstrates that DNS semantics do not require the usual UDP or TCP path.
This belongs in the transport gallery: unusual, ingenious, and very context dependent.
Primary source: https://twitter.com/scott_helme/status/982401557906862080