Best Things to Do with "change"
When someone is sleeping change their clock time and wake them up late for school/work.
At school on a casual clothes day bring a spare set of clothes and change in the middle of the day (Bonus: Swap clothes with a friend).
Get your friends phone and change all their contacts names to Star Wars/ Something Funny.
The next time a friend leaves their phone with you, take a ton of selfies and change their wallpaper to the best one.
If you have the type of light switches where you can change how bright they are, make them darker as slow as you can while people are in the room and see if they notice. XD
Go on you phone and change the number in your contact to another person/things number. (for example their crush, pizza hut)
Have your own things to do with "change" to add? Send one in!