A Google a Day - A Google A Day was an online puzzle game from Google which invites the player to solve a lateral thinking puzzle by using Google to find the answer. A new puzzle was added every day. The questions may be any of the following categories: Sport, Science, Pop Culture, History, Arts and Literature, or Geography.
Digital Breakout EDU - Library of digital challenges and problem solving activities designed to engage students in content connected to the 4 Cs of collaboration, communication, critical thinking, and creativity.
Google CS First - Students create computer science projects around different themes such as Sports, Art, and Fashion. Each theme contains 8 lessons of 60-90 minutes that can be tailored to fit your schedule.
Goose Chase - Blend together the tried-and-true fun of scavenger hunts with mobile technology and create a learning experience like no other.
TED-ED Riddles - Use engaging videos riddles to create customized lessons. You can use, tweak, or completely redo any lesson featured on TED-Ed, or create lessons from scratch.
How do you engage students in critical thinking? What resources do you use?