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A walk through a 12-foot high inflatable heart -- entrance is via the superior vena cava, naturally -- will be just one of the highlights for visitors to the Party for the Planet 10 a.m.-4 p.m. Saturday, April 23, at Discovery Green. The heart is just one of the interactive exhibits that are a part of Air Alliance Houston’s Earth Day Houston, the official name of the event.

The day-long event is the city’s largest Earth Day celebration and features several zones of activities concerning issues related to air, water, land and renewable energy. In the air zone, visitors can tour a mobile air monitoring lab and, in the land zone, there will be plant giveaways and wildflower information. New this year is the landscape zone that will feature the latest in green gardening products and techniques.

It wouldn’t be a party without live music and food. Among the entertainers will be the jazz band Miles Ahead and the Matchsticks. And the Urban Harvest Market will be open, offering organic produce, artisin ready-made foods and more.

The festival is admission-free. For more information, access discoverygreen.com or call 713-400-7336.

Other events:

• Cupcake sales to benefit Trees For Houston
This week, from Monday, April 18, to Friday, April 22, Sprinkles Cupcakes in Highland Village will donate 100 percent of the proceeds from its vanilla “tree” cupcake sales to Trees For Houston.

• Bayou Land Conservancy Earth Day Celebration
Plant a tree, make a trail, and get to know other interesting Houstonians. Friday, April 22, 2011, 9 am to 12 pm at Little Cypress Creek Preserve.