I had the opportunity to check out a new product from Brew Muse called a Beer Olive and review it for those of you who like to collect beer accessories. Bryce Bunkers, a Mechanical Engineer, is the guy behind it. He is currently running a Kickstarter campaign to build his initial inventory. The idea behind this product (also available in the shape of a hop cone) is to create active carbonation in your glass for the the entire time that you are enjoying your beer.
Basically, it borrows from the idea of etched glassware, but makes it portable. The Beer Olive is made of soapstone, which is food and dishwasher safe. You can get your own by making a pledge on the Kickstarter site. You can also have it personally engraved for a higher cost.
Here is a picture of the product itself—literally the size of a large olive.

The one immediate flaw that stood out was the choking hazard, so just be aware that it is in your glass at all times. The product was designed with a hole in the middle for this reason and does make a bit of noise in the glass so you are aware of its presence.
Here are my findings:
The beer I poured was a Paulaner Hefe-Weizen. As you can see the one on the left has the beer olive in it and has more head on it.

After 10 minutes you can see that the one on the left still has a slightly bigger head and the carbonation in the body of the beer is still present.

After 20 minutes the beer on the left still has more head on it (top view) although by this point the body had lost a bit of its carbonation.