1Solve a math problem
2Get a retail job
3Explore an area you haven't seen before
4Be around with new people
6Workout
7Eat your least favorite food
8Learn a new instrument
9Ask yourself tough questions
10Enlist in the army
12Learn a language
13Try a new recipe
14Be offline for a day
15Write a book
16Explore new music genres
17Take an academic course
18Do some gardening
20Try to break a world record
22Crack a smile to someone
25Try to solve a Rubik's Cube