It seems you can take just about any lasagna-like recipe you love and subsitute the zucchini for the pasta for a lighter dish more suited to the hot weather.
The trick to avoiding tons of water coming from the zucchini is to slice and salt the zucchini, lay them on a greased cookie sheet and pop them under a high broiler for about 5 minutes before starting to layer them. Be careful when opening the oven door, the amount of steam is kinda crazy.
Two medium-sized zucchini (like the ones in the photo) made a 9″x13″ three-layer lasagna that served six generously. We made a traditional Italian lasagna/parmigiana-type recipe, layering the zucchini with meat sauce, shredded mozzarella, grated parmesan cheese, one beaten raw egg and diced pre-sliced mortadella. It needed about 45 minutes at 375F.