Proper use of Rhubarb
Use only the stalks; the leaves are poisonous (or at least toxic if eating in high quantity)

Cut up the stalks in chunks from the bottom up to the where it becomes green (to keep the result as pink as possible) and cook down with sugar and enjoy in a crumble or a pie (with strawberries).

I've ate raw stalk dipped in sugar when I was a kid.

from http://www.rhubarbinfo.com/poison: 

Precautions for rhubarb gardening

Trim leaves from stalk immediately.
Don't use stalks from frost bitten plants.
Wash the stalks well.
Children should be taught to eat only the rhubarb stalks, preferably under supervision