Miscellaneous for my non muslim friends

Assalaamu alaikum wa Ramadan Mubarak!

As usual my non muslim friends come by home to share our iftar and they have a lot of questions about Ramadan, Qu'ran, Salat, even the Hjri Calendar.

So if you want to help me to do Dawah, any explanation or link will be wellcome and thanked.

Jazakallah!