So I was just playing around, and now (for the first time) everytime I go to google in the browser, I get the mobile calendar site which actually works every time I try it. I've tried a few times in the LastPass browser and just tried once in the regular browser. So, assuming those aren't flukes (I know the mobile version of gMail in the browser isn't reliable, but works if I switch to desktop) then i was able to go to "add event" in mobile GCal from the browser.

Is the browser version now working for others, too? (I'm no longer getting the message that GC is unsupported, but I can try to open an unstable version of the site.)