I would love someone to recommend some rap that I could safely play to satisfy my grandchildren and not assault my senses.
If it's purely to satisfy your grandchildren, find out what they like and play that. If it's for your own benefit maybe try something by The Roots - How I Got Over is a great album of articulate hip-hop with live instruments and some interesting samples. The album by John Legend and the Roots - Wake Up! - is a good mix of straight-ahead soul and thoughtful rap.
But I wouldn't expect grandchildren to like it.