Edited by birdie.lee - 5/7/13 at 1:04pm
I've never had Ovaltine, so maybe this won't be a good substitute, but when I want a hot drink that isn't coffee, tea or hot chocolate, I just heat up a mug of milk (or soy milk or almond milk), add some vanilla and possibly some honey or turbinado sugar, and spices - cardamom, nutmeg, or cinnamon are all very nice alone or in combination. It's a very comforting beverage.
I make peanut butter banana smoothies. They taste very unhealthy, but they only have natural peanut butter, a banana, and milk. So yummy!
If you do want chocolate, Lake Champlain has organic hot chocolate mix, and I think they have an unsweetened version too.