I wanted to feature a few sites that are awesome go-to tools for classrooms. Each one can be used at anytime during the day with a multiple of lessons, and used by the teacher (whole group) or by students. Take a look and think of the possibilities! =)
http://e.ggtimer.com/ - Quick and easy to use timer. Large print with countdown so it is great for classroom use!
http://www.scribblemaps.com/ - It uses Google Maps (something we already know) ;) but adds the ability to mark it up with arrows, lines, shapes, and words. Great for teacher demo with the whole group, or for individual student use. Consider students using it to create a map of their community,state, or country by identifying and marking major buildings and sites.
http://markup.io/ - Markup.io provides a way to mark-up any webpage that you want. To use it you just have to drag the bookmark image to your bookmarks bar (or install the chrome extension if you're using the Google Chrome browser), and then when you're on a site that you want to mark-up click it!
https://bubbl.us/ - Create mind maps. You can get started right away by clicking in the "Start Here" bubble, then just hit enter to create a new bubble or ctrl+enter to add a stem or "child bubble".