If you are familiar with how google usually hides its Easter eggs, it isn't too hard to find. In the case of Glass the Easter egg can be found by going to Settings -> Device info -> View licenses -> Tap the touchpad 9 times -> Tap Meet Team
This Easter egg is by far one of the most impressive ones that I've come across. What is it? It is a 360 degree panoramic picture of the Google Glass team. The entire team is circled around you. If you want to look at the people to your left, you turn to your left. If you want to look at the people behind you, you turn around. You can also look at the ceiling or at the floor. This gives you an idea about the possibilities that can come from Glass and some ideas of features that we can expect in the future.
Here is a video I found that demonstrates how to find the Easter egg and what it does: