It's gray and overcast and drizzly here in New Jersey, and it's going to be like that a lot over the next four months or so, at least when it's not snowing.
All these gray days can wear you down with the winter blues, even if you don't have a diagnosis of Seasonal Affective Disorder (SAD -- see Wikipedia). So if you can't fly away to a warm and sunny beach, you can at least bring some of that sunlight into your home with a bright light -- to provide both more lumens than an ordinary bulb to make a room glow, and a full spectrum of white light closer to the natural sunlight that you are craving.
For example, we've been trying out the Verilux HappyLight line of sunshine supplement lights. The HappyLight 6000 provides up to 6,000 lux of white light for $89 in a unit that's easy to carry -- 12 x 4 5/8 x 3 inches and 2 pounds. It uses a custom 36 watt Verilux Natural Spectrum bulb that lasts up to 10,000 hours ($24.95).
This puts out a very bright light -- 6,000 lux is not quite full daylight, but close (full daylight is 10,000 lux and up -- see Wikipedia). The unit also has a high/low brightness control.
Verilux also offers the larger HappyLight Deluxe with 10,000 lux and 19" tall ($189 -- shown in image), and the smaller HappyLight 2500 with 2,500 lux ($34.95) -- at 9" tall and 1 pound you can buy multiple lights in combo packs.
Verilux recommends positioning the HappyLight 6000 one to two feet in front of your face, although offset on a diagonal, so your eyes can take in the white light. The recommended daily use to reduce sluggishness and lethargy is listed as 2 1/2 hours. However, Verilux disclaims any medical claims regarding the use of the product, and states it is solely intended for use as portable supplemental lighting.
We don't have long-term experience with the HappyLight, but it certainly is bright and white, and it does make me happy to see it really light up the room.