Cram - create and share online flashcards. Play has a gaming feel to it.
EducaPlay - create lots of different activities, including crossword puzzles, riddles, word search, etc.
ePals - Connect with others globally
Factile - an on-line quiz game - like Jeopardy
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.
Kahoot - Create, play and share fun learning games for any subject, for all ages, for free!
Learn Around the World - Use technology to connect students and educators globally. They have events and collaborative projects where students can work with people in different countries, and virtual field trips for exploring foreign lands. LATW also has guest speakers and private events that teachers can take advantage of. Imagine speaking with someone who lives in Buenos Aires while learning about Argentina. Your students can ask questions and use their curiosity to spur discussion.
NearPod - create interactive lessons that engage the whole class.
PearDeck - engage the entire classroom.
Quizlet Live - Makes studying collaborative and competitive. Students love reviewing with Quizlet Live.
Quizziz - A fun multiplayer classroom activity, that allows all your students to practice together.
Socrative - empowers teachers to engage their classrooms using the space race, multiple choice, true-false, and exit tickets.
Skype in the Classroom - go on virtual field trips, collaborate with classrooms globally, have mystery skypes or invite in guest speakers.
Super Teacher Tools - This site has many cool tools...random name generator, timers, countdowns, Jeopardy, Speed Rocket Game, Who want to be a Millionaire, Speed Match, online spinner.
Thinglink - Annotate images and videos
Word Wall - Multiple templates to create your own teaching resources that engage students.