Ever since I got my car, it has always bugged me that the interior dome light didnt work. The bulbs appeared to be in good shape, but I always figured that it was a fuse or something, somewhere. Earlier today I decided to do a quick search, and found a Youtube video showing how the electrical contacts in the light can become corroded and no longer make proper contact.
So I decided to give it a shot, and it worked! The contacts had a lot of blue buildup on them. A little sandpaper and elbow grease, and 10 minutes later I had an interior light for the first time.