A few people have started using appointment slots in school to manage things like parents evenings. Really easy to use and set up. You could do bookings for tutorials with students, parents evenings or interviews with students.
I've made a brief video on how to record tutorials and run webinars using Google+ and YouTube. Y9-11 will soon be able to use Google+ along with Y12-13. This means you can do this with them. Its really easy to do and does not require any special software. You can: Record video tutorials. Run online question and answer sessions. Run interactive tuorials. Have all the content popped into you YouTube channel for future use and playback.
You may have created Google Sites at school and expect people to use them. However, do you know how many people actually do? You can get an enormous amount of data about your websites by setting up Google Analytics for each of your sites. Takes a few minutes and can be very revealing about how your sites are actually used (or not!).