Choose-Your-Own Cover Band T-Shirt from thinkgeek
The process is simple: 1) Take any random phrase; 2) Insert a band that said phrase bears some relation to; 3) Profit!* And the best part is, the washable marker lets you create new cover bands every time you wear the shirt. It even comes off with a wet paper towel for sudden, mid-day inspirations.
Here guys, to get you started: