Is it possible to store erb templates in database? How?
Sure it is.
But I think, this is not the best solution if you only need some pages with same layout and different content.
If you really want ERBs saved in database, create some model with your ERBs saved in. Then you can call in controller code like this, to render that ERB.
erb = ERB_model.find(...)
@some_model_data = SomeModel.find(...)
erb = ERB.new(erb.source)
render :text => erb.result, :layout => true (or another)
Watch ERB.new parameters.