OK.. is there a trick to this? Somehow in 25 years of driving, I've never had to replace one of these upper brake light bulbs.

I seem to have one in the "series" out -- from outside it appears that there are maybe 6 bulbs in a row, and #2 or #3 is not lighting up. Looks like a kid smiling with a missing tooth.

How does one get in there?

 

Push the housing towards the back window then lift up from the side closest to you. You can then lift it out to unscrew the holders for each individual bulb.