Post-it-notes are a perfect idea for making your students more energetic and willing to learn. They are available in many shapes, colours, sizes. In case of emergency you can replace them with small pieces of paper. They are versatile because you can use them to practise different aspects of language. They don't require a lot of preparation time. Finally, they make our students move which helps them learn in a more effective way. 
There are so many advantages, so let's try and use them to make our lessons memorable and full of fun.

This is a set of exercises in which online materials about the concept of the Underground Railroad are used. The activities are designed for a 90-minute lesson with students.

1) Briefly explain the situation in the US – in 19th century before the Civil War some states were so called free states where black people did not work as slaves but were treated as free people. Southern states promoted and encouraged slavery.
2) Introduce the concept of the Underground Railroad by showing the slides from the following website:
http://teacher.scholastic.com/activities/bhistory/underground_railroad/slideshows/escape_slides.htm
Ask students to work in pairs and recall together as much information as possible, they can take notes. After this check understanding by asking some comprehensive questions:
            - What was the Underground Railroad
            - Who were “conductors”? What was their role?
            - Why did slaves have to run away to the North?
            - What did slaves’ life on the plantations look like?
            - How did people help the runaway slaves?
            - What dangers did slaves face on the Underground Railroad?
3) Show the map of different routes of escape for slaves. Do the tasks attached to the map - http://eduplace.com/kids/socsci/books/applications/imaps/maps/g5s_u6/index.html#top
4) Ask students to read a text about Harriet Tubman and do the comprehension task. Analyze vocabulary with students. Ask students to write a 3-sentence biography of Harriet Tubman.
http://mrnussbaum.com/pdfs/tubman.pdf - reading about Harriet Tubman
5) Play the first episode of the series called "Underground". Describe briefly that the series shows a fictitious plantation in the southern states of the US before the Civil War. The slaves living there are planning to run away. The story is based on the history of the Underground Railroad.