The use of office hours is a great solution.
I get INUNDATED with requests for meetings. If I said yes to all these coffee requests, I think I'd buy some Starbucks stock beforehand :-) Most of my requests are related to one of the major "themes" of my life/work -- generally they include: 1) helping other entrepreneurs/VCs/students or 2) my work on education reform. Today, I informally designate time a couple times a month on my calendar as office hours. I generally run an "ed reform" office hours block on my calendar once a month, and an "entrepreneurs" office hours block every 2 weeks.
It would be great if I could drive folks to a web-based tool (optimized for "makers" like us) to help schedule these requests, because I find just managing the flow itself is fairly taxing. The tool would let me pick the time range of hours, topic and duration of each meeting. It would also let me designate office hours as meetings or calls, and if meetings, designate a venue. It would have to somehow be respectful to the requester so I don't seem like an arrogant jerk for using a scheduling tool.
Further, I am willing to pay perhaps $12 per month or so for such a service. Maybe I am the only busy guy willing to do such a crazy thing. (Ok, Steve Blank fans...)
1) Does such a tool exist already? 2) If not, anyone want to build one?