Waffles, pizzelles, and other such foodstuffs are delicious, but making them requires the appropriate type of iron. Most people don't want to spend the money, or give up the kitchen space, necessary for having a waffle iron, especially since it only makes waffles. Grilled meat and vegetables are likewise
delicious, but grills are expensive, and many people don't have a private backyard in which to put them.
Enter Griddle-inserts. These corrugated metal plates fit onto most common cookie sheets, and are designed to allow your oven to mimic the operation of irons and grills.
The waffle-iron design consists of a circular or rectangular pan with 1 or 2 waffle-shaped indentations, and a matching pan to place on top of it. Simply put your batter in the bottom pan, put it on a cookie sheet (to catch any overflow), put the matching pan on top, and bake in the oven for n minutes at m degrees.
The grill design looks like a cooling-rack slightly smaller than the cookie sheet with which it is to be used. Legs about 1-2" high allow the grill to be set a small distance above said cookie sheet, which catches all the drippings. Just set the oven to bake, and check back in periodically to flip your foodstuffs.
These have several advantages over traditional grills and griddles. Being little more than ridged sheets of metal, they are very inexpensive and take up very little of your precious storage space when not in use. They are easy to hand-wash, and smaller models may even fit in your dishwasher. Unlike grills, Grill-Inserts don't require dangerous gas-tanks, open flames, or a backyard. And, since the grease is collected in the cookie sheet, rather than staying in the meat, the Grill-Inserts means of cooking is much healthier than most other oven meat-cooking methods.