Indian summer is here! Catch it before it leaves.

Free public lecture by artist Beth Coleman, 5 pm Friday at the San Francisco Art Institute.

Free Gregorian chant workshop on Saturday morning in the Castro.

Intro to Sewing at the Crucible in Oakland, Noon to 4:00 on Saturday.

“American Splendor” author Harvey Pekar and comix artists sign “Best American Comics” at Booksmith on Haight St., Saturday at 7:00.

On Sunday from 1:00 to 5:00, the MIssion Lake Project sponsorts a “perimeter bike race” and “lakeside” barbecue, Mission Park and Playground (Valencia Street between 19th and 20th Streets). The joke is that Laguna Mission no longer exists, but for one beautiful summer afternoon, these artists will pretend it does.