One thing that has been a challenge for LEGO builder is lighting. The LEGO Group had lighting sets but discontinued them years ago, with only light bricks for Power Functions remaining. In their place, there have been a few people that have created light kits for LEGO creations.
Modulite, is designed to light interiors.
These kits are compatible with other e-Lite kits by Rob and Stuarts's company, Lifelites and can be chained together to light larger models.
The Modulite kit has three light boards, 2 6-inch extension cables, and a battery box that uses 2 AAA batteries. Price is $15.00 plus shipping and orders can be taken here.
Good work, guys!
EDIT: Added Stuart Guarnieri - my apologies for not including him!