A not very energy efficient but interesting possibility is to add an Endless Pool either in the basement or as an additional room. This is effectively a treadmill for swimmers. The claim is that this uses about the power of a hot tub, but what is that? With a cover it is claimed to not produce too much humidity.
In addition to house lighting, it is possible to have solar powered garden lighting. An example is a "solar candle" or the range of products available from C. Crane radio and lighting.
In order to extend the season when it is reasonable to sit outside on the patio or deck, there are a number of gas fired patio heaters. Socal gas has a discussion of what is available and the energy requirements. They suggest that flexible hose attached to a gas outlet is available. "Mushroom patio heaters can be easily connected to a gas stub, with a hose extending from the unit to your home. Since their efficiency is affected by the wind, it's best to install them in a sheltered area, providing specified minimum clearances for combustibles.
Permanently mounted, directional gas patio heaters can be installed in eaves, along walls, or on specially designed posts. While they generate fewer BTUs per hour, they are less affected by air movement, adding to their efficiency. Gas patio heaters direct warmth downward, generated by a heated ceramic element.
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Manufacturers of gas radiant heaters include Infrared Dynamics who produce free standing and wall mounted patio heaters (scroll through their entire page to get to the wall mounted units). TNG in Westchester, Ill. seems to be the closest distributer of their products.