In the 70s and 80s, the iron-on was king, a Camaro his chariot. Bring back that patchy glory, at Iron.
Pop by Iron's Atwater Village shop to pair up one of their 200 designs with a t-shirt -- they carry American- and Alternative Apparel blanks, or you can bring your own -- and they'll do the heat-steaming dirty work for you. You'll have your pick of rock royalty (Zep, AC/DC, The Ramones), superheroes (Batman, Wonder Woman, Kareem Abdul Jabbar), and, of course, classic iron-on fare (Trans-Ams, Naked Ladies, Unicorns for people who don't like naked ladies).
For a $5 fee, Iron'll also make custom iron-ons from any .jpg or photo you bring in -- though if a vintage muscle car doesn't do it for you, you're probably more into ironing than ironing on.