Have you seen the new MSQC Skate Board quilt Tutorial on You Tube?
I am making my 18 year old son a red white and black quilt using a pattern called Jungle Fever. He chose the colours and the pattern (there was on made up in my LQS.) It is a fairly easy quite that uses 10 inch squares (I cut my own). You stack up 3 different ones then cut them up and shift each pile top to the bottom etc, and sew them back together again. There are 5 different cutting layouts.
I have about 18 different fabrics I am using.
I was going to make a disappearing 9 or 4 patch, but am enjoying this project.
I am mostly a beginner quilter, with only about 3 quilts (one completed) under my belt (and three rag quilts).
My son is a nerd he would not have wanted a 'manly' quilt with a outdoors theme. He did look at a labyrinth quilt in a different LQS, but he said he would not feel comfortable looking at it. No where for his eyes to settle.
If your grandson likes Dr. Who there are quite a few Tardis patterns. If he likes Nintendo you can find Mario quilt patterns too.