I now know first hand why the combo of Bike-Run is called "Laying Bricks"
In a triathlon at the end of the bike leg your suppose to hop off the bike and start running. The objective is to make this transition as fast as possible.
As you take the first 30 or so steps of the run it becomes clear that your feet are the "bricks"
The lactic acid build up in your legs is incredibly uncomfortable, you could equate the sensation to someone taking a syringe and injecting corn syrup into your muscles.
I have a new found respect for people that can do this. It is one of the most unpleasant exercise related experiences I have had the displeasure of performing.
I am now wondering how unpleasant the sensation of jumping on a bike after the swim will be because I always save the swim for the end of my workout (to cool down in the water)
Guess what I'm going to try to do on Friday:)
I think that the term "bricking" refers to performing 2 of the 3 tri events in succession during training.
Learn something new every day.

Exercise
Bike 30 min (@ 90 rpm average speed this works out to about 19.something km's)
Run 4 km (I think I could have done the whole 5 k today if I did not do the bike thing first, ran out of legs)
Walk 1 km (to complete the distance)
Swim 1km
I skipped the weights today so I could do the "brick" thing.
(Weights would have been easier)

Diet
Breakfast
Cereal with skim milk
Snack
None
Lunch
2 pieces of whole wheat toast with jam
Snack
V8 X 2
Dinner
800 Pounds of pasta with meat/tomato sauce with veggies smothered in cheese, milk
Snack
Coke, 10 chocolate chip cookies, glass of skim milk, 2 cups of coffee
(I never mention it in the diet roll but I drink a minimum of 6 liters of water every day)