Layer tennis is a design game made popular by Coudal Partners. Two competitors (myself & Aaron Liechty) pass design files back and forth, riffing on the same work under extreme time constraints. Each 30-minute "volley" is posted live as it is created, along with commentary (Jacob Liechty).
Sondra Eisenstat agreed to help us with the thankless task of posting it all online, since the rest of us were pre-occupied with writing & designing under pressure.
The battle took place on Sunday afternoon. The full experience is still available on the Exit Strata blog, but here are the volleys: