In society, we have a small number of hand gestures for certain key activities. There must be something special about these activities -- that they need some amount of emphasis, or to be communicated in noisy environments or across a crowded room. Here are all the gestures that I can think of (add more in comments if you think of any). Picture them in your mind as you read them:
The bill (in a restaurant)
Phone / call me
Yesterday, I realized that we have silently agreed on a new gesture in the last few decades: Mouse click
I find it interesting [and, as usual, I feel it unnecessary to provide the obvious caveat that you probably won't] that these gestures are weird exaggerations of the activity that they represent. Also, note how some are more common that others: I can think of a gesture for eat/eating, but it seems much less standard than drink/drinking. Similarly, there is one for typing (well, really, any keyboard activity such as piano playing), but it doesn't seem as useful as the mouse one.
Have I missed any? Do "the kids" have a hand gesture for texting, or hanging out on the Face Book web page? As I've said about many things in the past, I'm sure that there's a sociology thesis in there somewhere (probably titled something like "Evolution of Colloquial Sign Language in The Internet Age"), and probably no one will ever write it.