In Google Labs, developers created and launched software prototypes, providing users the opportunity to experiment with these prototypes and offer feedback. However, in July 2011, Google decided to discontinue the Labs project. Whether or not this was a good idea is debatable, since many of the developments were, at best, frivolous, while others (Google Maps, Google Reader, etc.) went on to become building blocks in the foundation of the Google empire.
The end of Google Labs, along with recent renovations in Gmail, led many to believe that the Labs feature in Gmail was also discontinued. However, it‘s still alive and well. One cause of this confusion is where Gmail Labs is now located. Before the recent changes, Labs was accessed by clicking the Options gear icon and selecting either Mail settings or Labs from the menu.
Old Look (still temporarily available)
In the new look, click the Settings gear icon, and select Settings from the menu.
In Settings, click the Labs tab and, either scroll through options, or search for a particular lab.