Rowing 
Get on your Concept 2 -> Press Menu -> Select Workout -> Custom List, and select v1:00/1:00r..7 ! Take it for a ride for 7 intervals.
1:00/1:00r
2:00/2:00r
3:00/3:00r
4:00/4:00r
3:00/3:00r
2:00/2:00r
1:00/1:00r
Time: 16 minutes
Distance: 4035 meters

Notes: Goal should be to match or improve on distance recorded on way up during your trip back down the ladder.