The reading program that we're using has different units - they're each about 6-8 weeks long and during the unit we're supposed to do a lot about the particular theme. For example, right now in third grade, our unit is "Money," so all the stories we read are about money, the kids are supposed to keep track of observations about money in real life, etc.
One of the fourth grade units is something like "From Mystery to Medicine." When Warren and I were at Target some time back, they had the M*A*S*H boxed set - which is pretty obvious because it's so BIG, and it's called something like "Martinis and Medicine." I keep getting the two mixed up in my head and I know that people are going to look at me really funny when I say something like, "So, in fourth grade, when they're on the Martinis and Medicine theme..."