The folks at Zilker can help you learn how to collect and press plants in your own garden. 1-4pm. $2 adults, $1 kids.
Foundation Communities is still here to answer questions about and help with signing up for Obamacare during open enrollment, Nov. 1-Jan. 31, 2016. Mondays through Thursdays, 9am-7pm; Saturdays, 9am-4pm. See website for what to bring. Free.
Foundation Communities Financial Center, 5900 Airport
Learn about how to fight "environmental racism" and how to promote a fossil fuel free economy. 1-3pm. Free.
Go back in time when helmets were thin pieces of leather and gloves weren't seemingly covered in glue. This exhibition features rare artifacts from Vince Lombardi, Sammy Baugh, Tom Dempsey, Tom Landry, and more. Try on some vintage gear and hit the instant replay booth. Through Jan. 3. $12 ($8, kids).
Learn more about one of the most controversial Olympics courtesy of this mobile exhibit from the U.S. Holocaust Memorial Museum. Exhibit is open every day. Free.
First night of the Zilker holiday tree. Lighting ceremony begins at 6pm. Runs through Dec. 31. Prelude music by the Austin Civic Wind Ensemble and more music by the Barton Hills Choir. Visit the website for updated parking details. 6pm.
Zilker Park, 2100 Barton Springs Rd., 512/974-6700
The supply of platelets has fallen to an unsafe level. Anyone who is able is urged to make a platelet donation appointment as soon as possible. Platelet donation may be done every 7 days or 24 times per year. The entire process from the time a donor walks through the doors until they leave is approximately 1 to 1.5 hours. Call to make an appointment. Open seven days a week.