Recently there was a jug pouring competition, and I got to thinking if this was the question with the most number of moves. It turned out that it was. If you have three different sized jugs all less than or equal to 10 litres, and only one of those jugs full, what target volume would give you the most number of steps.
You can get as many as 8 steps required. (10,9,2) → 8; (10,9,1) → 5; (10,9,1) → 4; and (10,7,3) → 5. So the question has pretty much the only interesting optimal result.
Here's another one for you (since I wrote the code already, it seems a waste not to use it).
Starting with 15l in a 15l jug, an empty 11l jug, and an empty 4l jug try to get to 13l.