Chocolate Fountain -- Choco recipe

Hi everybody. I recently received a chocolate fountain machine which I wanted to use for my son's birthday but I had one basic problem .-- I didn;t know what chocolate or what chocolate mixture to use. Does anyone have a recipe? Also what cookies and fruits are good / popular to put in my chocolate fountain bar?
I also noticed some people use the choco fountain machine for the nacho cheese. Does anybody have the recipe for that too? Thank you