Looks very promising, but perhaps not complete? The links don't seem to generate for me. And I can't switch "reserve time" to "available time".

Is there nothing like this out there already? I could definitely see myself using something like this.

Nice work!

Reminds me a bit of this hack, http://rbtying.github.io/whencantimeet/

Does it work with multiple accounts? I have a work vs. personal account, each with blocks of time on them when I'll be busy.

also look at: http://www.timebridge.com