This is one of my favorite exercises. What you do is, select a character - one you especially like or one that needs some more flesh - and pick a few ages for the character (i.e. 6, 14, 32, etc.) After that, create life events that happened for that character at the given ages.
Let's have some fun! I'll do an All through the Years for Eeyore from Winnie the Pooh to show you.
Age 3: His mother gives him a ribbon for his tail on his birthday
He pretends a rock is his pet and talks to it.
Age 10: His father teaches him how to build a house out of sticks - without much luck
He sees a myserious bouncing creature with a long tail in the woods at night, but doesn't know what it is
Age 25: Decides that his favorite activity is staring at the clouds; Pooh, Piglet and Tigger worry about him, but Eeyore tells them it makes him happy.
Follows Christopher Robin to school and becomes the first 100 Acre friend to multiply
Age 40: Tries to write a book on the things he thinks about, but ends up just thinking about them more and never writing them down
Rabbit leaves to visit family and Eeyore is asked to tend his garden. Eeyore accepts reluctantly but finds he likes planting and the smell of dirt. Eventually spends more time with Rabbit, taking care othe the garden
Age 70: Because he's too old to stand the elements, Christopher Robin prepares a place for Eeyore to live in his house.
The gang starts meeting every day at Christopher Robin's for honey and tea and to talk, at Eeyore's suggestion