Flippity.net

Easily turn Google Spreadsheets into awesome useful tools using Flippity.net.   Go to Google Sheets to add the Add-on Flippity, or go to http://flippity.net/ and select which tool you want to use.  One of my favorites is the Random Name Picker.  You can pick individuals or groups.  There are other cool ways to use flippity.  Other tools include: hangman, word search, crossword puzzles, bingo, as well as a certificate maker.