cloudsdemo : http://ghoulsblade.schattenkind.net/love-webplayer/
WARNING: still incomplete, some of the love api won't work yet
usage: unpack .love file (rename to .zip), add the .js files and the index.html from love-webplayer, upload the whole folder to webserver, open in browser, play
EDIT: i guess we'll need love.web api next to love.phone/love.android soon
EDIT: if you want to discuss pure html5/canvas (without webgl), NaCl, flash or similar alternative tech or browser plugin, please make a new thread instead. I'm only interested in a webgl implementation and the others have already been suggested.