Grad Student: "Um, so, I was wondering ..."
Faculty Member: "Yes, what were you wondering?"
Grad Student: "Well, uh, I'm putting together my committee, and given the fact that I've taken a couple of classes with you, and also given the ways my interests line up with much of your work ..."
In this way or ways similar, grad students across the land pop The Question to faculty in their departments. Will you be on my committee? Of course, on the faculty side of things, we wait for this magic moment, look for hints, gossip amongst ourselves, and make sure to respond accordingly. In lieu of a ring exchange, files are made up and forms sent to the proper office.
It makes me wonder, though, if things oughtn't work the other way around with faculty asking students if we can work with them? Or at least offering? I remember hearing a story about Dale Bauer, who I was blogging about last week, asking a grad student if she could work with him. It was really quite simple: Dale was new to UIUC, she'd heard about this guy's work, so sent him an email.
We could at least consider developing a parallel practice, based on Dale's offer, to let grad students know we think their work is groovy and cool and we wanna work with them. This wouldn't need to eclipse the current proposal system, merely complement it. I say this because there is something nice about having committee configuration entirely in the hands of the students.
One last thought: felicity conditions seem to mandate that popping the question happen in person; is this true? Have people "asked" or "been asked" over email? the phone? IM?