How to effectively supervise grad student calculus teaching assistants (TAs)?
I'm not in math, but I have supervised several times multiple sections of a first-year software design course taught primarily by grad students (usually I also am teaching one of the sections).


Weekly meetings are helpful, at least an hour, especially for first-time TAs
Collaborating on course content (presentations, exercises, quizzes, homework, exams) via the cloud (e.g., Google apps) is great
My policy is to share all my content with new TAs when they come on board, with the agreement that they'll improve and re-share it back.
I try to get extra $ for "tutoring" hours for them, outside the course, so as to make the work less painful. Anything that boosts morale and shows you're on their side is great.
I try to nurture leadership within the group, as turnover is high.
I used to pay (out of my pocket) an end-of-semester team-building social outing (I felt it was worth it, to have motivated TAs). However, when the department chair found out I was doing it, he started covering the cost from then on, if I invited him, too (this has become a normal thing, since it's essential to get and keep for a while the motivated TAs). 
If you can approach it as a management problem and apply some management techniques (don't take on their monkeys), it's feasible. Also, I scooped a few good research students (and was able to spot some I wouldn't work well with) thanks to the experience. 
My department doesn't rotate this kind of responsibility, since courses are generally "owned" by only one or two professors. We are unionized, and have considered having this kind of supervision recognized formally in terms of teaching load (which it still is not). It comes up every time our collective agreement is re-negotiated, but the % of faculty it affects is small. The P&amp;T committees take it into consideration, however.