Normal childhood means, a child brought up in family environment, receiving all the basic needs i.e. Food, shelter, parents, love, care, education, sports, etc etc. Some children become victim of sexual abuse, violence, child labour and some are nurtured as an orphan. So they are considered as abnormal childhood.
Children that are happy.
My normal and probably many others would be some peoples nightmares or some peoples dream :) its all about perspective and how you choose to grow from your childhood experience. There's no freakin normal and that's freakin awesome :) freakin is the word of the day ;) I just saw how old this Q is and I have no idea how I ended up here :o freakin freaky :)
Normal childhood development has toddler-age in which children are exploring their bodies, seeing what is happening around them and learning to behave in stimuli. Here is a link to a very useful article from where you will get a lot of information:
Normal childhood
Normal childhood