I made my three boys sports-themed quilts. They LOVE them!

What are they into? Play along on that theme.

sports
nature
geometric patterns
their college mascot
if they are in the millitary, firedepartment etc.
any interests they have like motor bikes, surfing etc.

Log cabin quilts are also good designs, I had made one using all money fabrics for one son and the other all his favorite sports, they loved them!