Love love LOVE Focusmate! I've been using it for 18 weeks and am averaging 26.4 sessions per week. Wooo!
Feature idea/request #3: Give users the ability to book a session with a specific user *when that other user doesn't already have a session scheduled.* And doing so could trigger a tentative calendar invite to the invited partner, which they could accept or decline.
For example, one of my favorites is named Matt; if he and I are in a session right now and agree "hey, this was great; wanna work together the same time tomorrow?", within Focusmate's current build, I would have to book a session first, then give Matt the green light to go in and book that session. But it would be super useful if I could just go ahead and book a session for both of us, even if the session is tentative by default for Matt.