1. Listen to a hundred cars' soundsystems form the world's largest synth orchestra at the premiere of Ryoji Ikeda's "A [for 100 cars]." The free Red Bull Music Academy Festival performance takes place at 131 South Olive Street in Downtown L.A. at 5:30pm.
2. Hop aboard the Halloween Ghost Train, a family-friendly ride through a sort-of-frightening stretch of track in Griffith Park. The Los Angeles Live Steamers Railroad Museum tradition runs from 7 to 10pm; tickets cost $20.
3. Eat for a cause at Winsome's No Island Left Behind, a fund-raiser from 3 to 7pm that features Puerto Rican fare, oysters and cocktails, all for $25 per person and to benefit the One America Appeal,
For more events, check in with Time Out throughout the day.