If you have Windows 8 in your lab. you'll want Music Maker Jam - a sort of Garage Band" for Windows 8. It doesn't seem to have the complexity but it is a great thing for creating and has a whole different feel. Install it in labs for students to mix their own music.
If you have Windows 8 and touch screens like I have in my computer lab. Fresh Paint is one you'll want to have. It supports up to 5 fingers and you can mix colors. Yes, there's an in app purchase, but I'm going free for now. Sort of like an Art Rage.
Here's instructions on Google now within Google Search. I'm setting this up on my ipad and iphone to play with it. I've heard it is a good substitute for Siri if you have an older iDevice that can't get it.
Google now is worth installing on iPad and iPHones and you can get it even if you don't have a Droid phone. This instruction at PC mag tells you how, but it is part of the Google Search app. Download that and follow these instructions to set it up. There are privacy concerns so I wouldn't do this with students. Educate yourself but you might just get a handy personal assistant.