Trying to convince the class that test-driven development + DTSTTMPW ("do the simplest thing that might possibly work") + pair programming is the way to go, our software dev prof had us split in groups of two that would each get a turn to
1. add a unit test
2. edit the code so it passes the test
3. commit the change

The goal was to write a java class that converts integers to roman numerals.
Each group had only 2 minutes before the prof made them revert their changes.
After 45 minutes the code was just 10 lines of this:
if ( n == 1 )
return "I";
else if ( n == 2 )
return "II";
else if ( n == 3 ) ...