Computer Class: 
Try these online resources.

http://www.beepbox.co/
BeepBox is an online tool for sketching and sharing chiptune melodies.

http://voxelbuilder.com/
Tools for creating voxel structures.

http://kyucon.com/qblock/
Qblock

Puzzle Maker
http://puzzlemaker.discoveryeducation.com/AdvMazeSetupForm.asp?campaign=flyout_teachers_puzzle_maze

http://www.mineconics.net/
Online Minecraft circle and elipse generator

http://oranj.io/blog/VoxelSphereGenerator
Use this tool to make spheres for Minecraft and the like.

http://www.plotz.co.uk/
FREE HTML5 Modeller for Minecraft. Generate Spheres, Ellipsoids, Torus
 and more in your web browser.