Here are some of the features currently available – note whenever you pick one, you are not only required to hit Save Changes, but sometimes also to enable other settings (like keyboard short-cuts) for this to work:
- Quick links box: This will add a box to the left side to which you can add any Gmail URL... like, for instance, a Gmail search for in:inbox is:unread to see all your unread messages of your inbox. This could come in very handy.
- Different stars icons: Lets you define a couple of different star icons. Traditionally you can only either add or remove a yellow star to a mail. With this feature you can click the star several times to rotate its image. (Google names this feature “Superstars”, which is a bit of a pun that might make some mistake it for a “automated icons for VIP friends” feature at first.)
- Fixed width font: Enabling this will trigger a new entry in the “Reply” menu that lets you switch to a non-proportional font.
- A Snakes game: Well, perhaps something to surprise your friend, though not useful (or a terrific novel game) in itself; enable this, then enable shortcuts, and press “&” to bring up a game of snakes.
- Mouse gestures: When you enable this feature you can hold the right mouse button and then move the mouse upwards to jump to the inbox, from any place. Moving left-ways goes to a previous conversation, moving to the right goes to the next.
- Random signature: This will load one of several signatures available in an RSS feed file.
Other Labs features are profile pictures in chat, custom keyboard shortcuts, the ability to place your signature above the quoted message, custom date formats, hiding your friends’ status to save screen space, an anti-email addiction tool that will block the screen for 15 minutes and makes you invisible in chat, as well as an experiment that hides the “unread” count for the inbox, labels and so on. Google in a blog post on the subject says more features are “on the way.”