As we noted before, Microsoft has partnered with Katy Perry and Maroon 5 to hold shows on the 8th, the day that Windows Phone 7 launches in the US. Tickets will be given out at select AT&T stores. You can find our previous coverage of the events and their details here.
This is what the chalk marks look like, image via our friends at WinRumors:
While the art might leave something to be desired, we will say it again: Microsoft is determined to have the US WP7 launch be a success. This is their hail mary mobile pass, and after a strong international start, Microsoft wants the US launch to follow suit.
If you see any chalk outlines in San Francisco, let us know, we suspect that a similar campaign might be underway. Are you going to go to one of the concerts?