You never know what road kids will take you down, I've been to my fair share of ball games, but I'm always more comfortable at their jazz performances.
I used all kinds of easy to care yarn from Cascade, Berrocco, Crystal Palace, Blue Sky... I made sure every pattern was something my kids would be comfortable wearing in colors that I loved.
Hopefully you'll find lots of inspiration.
Whatever book or design you end up selecting. Please post a photo of your creation so we can all admire it!