The Jet Propulsion Laboratory (JPL) will hold its popular annual open house on Sat. May 14 and Sun., May 15, from 9AM-5 PM both days.  Admission and parking is free:

This popular event celebrates JPL's accomplishments with exhibits and demonstrations about the Laboratory's ongoing research and space exploration. Many of the Lab's scientists and engineers are on hand to answer questions about how spacecraft are sent to other planets, how scientists utilize space technologies to explore Earth and how researchers are searching for planets beyond the solar system.

The Open House is a fun and educational experience for children too, with special hands-on activities designed for kids. Admission and parking are free. 

The following items are not permitted at this NASA/JPL Event: weapons, explosives, incendiary devices, dangerous instruments, alcohol, illegal drugs, pets, segways, and all types of skates including skateboards. No bags, backpacks or ice chests are allowed, with the exception of small purses and diaper bags. 

Your entry on NASA/JPL property constitutes your agreement that you, your vehicles and your personal belongings are subject to inspection. 
JPL is located at 4800 Oak Grove Drive in Pasadena, off the 210 (Foothill) Freeway at the Berkshire Avenue/Oak Grove Drive exit. Parking is available near the Oak Grove main gate and the eastern boundary of JPL, accessible from Windsor Avenue via the Arroyo Boulevard exit off the 210 Freeway.