Soshiku is a simple but powerful tool that manages your high school or college assignments. Soshiku keeps track of when your assignments are due and can even notify you via email or SMS.
Phuser describes itself as a social network for "your real-life friends", and as such allows users to host private spaces to plan events and meetups with each other. Users amass friends and then can contact them via "phuses"by SMS or email. Phuses are similar to message board topic discussions, with the distinction that phuses are only open to the friends you select to send them to.
This is apparently used by bands to broadcast info. Can you imagine yourself broadcasting to your students cells reminders about papers due dates, and other reminders.
The easiest and most entertaining way to collect feedback from your audience: project polls or message boards on a large screen, have everyone send their input via their cell phones and see results instantly!