It’s the Transbay Calendar for mobile devices. The Calendar is visible normally at transbaycalendar.org or bayimproviser.com. (The latter, devised by local fan John Lee, uses the same database but also links to artist biographies and sound clips, among other goodies.)
Both of those sites were devised about a decade ago, probably more, so the mobile app is a serious upgrade. The biggest feature, IMHO: In addition to calendar listings, you can link to maps to where these venues are. Creative music can be shown in some pretty darned obscure places; I really could have used an app like this when I first started exploring the scene. (That was back in the ’90s, though, when not having a cell phone was the norm, and nobody said “app.”)
It’s all yours for the low low price of $0. But wait, there’s more!
Uh… no, actually there isn’t. But for $0, it’s a pretty good deal, eh?
You can download the app at appshopper.com/utilities/transbay-calendar.