The sun lamp can serve various purposes. There are some that may be available to assist with tanning, and others are supposed to help with reading by reducing the glare from objects that can cause eye strain. But ultimately, it's just a little twist on a a pretty safe, though admittedly not typical, gift of a lamp. Everyone can use a lamp and they can be easily exchanged.
Where to go:
You can search all over, but if you have an interest in energy efficiency a possible match is a sun lamp by Brookstone, the HappyEyes™ Floor Lamp. This lamp is specifically for reducing glare and thus reducing eye strain. This lamp also comes with a bulb that is supposed to last longer than bulbs of typical voltage.

HappyEyes™ Floor Lamp
(Image from brookstone.com)