WhooMS is a tiny public WMS server for those people who have a GeoTIFF and need someplace to serve it as WMS. I wrote it a while ago, but now its running for all to use.
It’s written in Ruby, using the Sinatra Web Framework, which basically means it can all fit neatly on one file. It uses Ruby Mapscript to read the uploaded GeoTiff and serve it out to the world.
Nice and simple and basic. Got a GeoTiff handy? (EPSG:4326) give it a go. whooms.mapwarper.net
The code for it can be found on github: http://github.com/timwaters/whooms
Main caveat: when the disc space gets full, the older files will be deleted to fill up space.