For the past 2 years, Disneyland has been hosting a special after-hours ticketed event series: Disneyland After Dark. Each event has its own theme, with special character meet and greets, photo ops, and lots of open attractions. Disney just announced the 2020 lineup, and the new series is the largest ever, with 4 different events to choose from.
 Source: Disney Parks Blog
The first two events will be hosted in Disneyland, and the second two in California Adventure. In addition to the usual exclusive photo ops and characters, each night also has its own entertainment:
80s Nite (January 29)
- “Flashback to Videopolis”: before it became the Fantasyland Theater, the stage area in the back of Fantasyland was Videopolis. For one night only, the 80s dance floor will return, complete with a hosted dance party.
- “Awesome After Dark – Fireworks to the Max!”: 80s inspired fireworks and musical entertainment.
Sweethearts’ Nite (February 12 & 13)
- Romantic dance parties across the park
- Couple photo ops with princesses and their princes
Pixar Nite (March 5)
- Dance parties across the park, each themed to a different Pixar world (examples given include the Incredibles and Monsters Inc.)
Villains Nite (April 30)
- Villains Cabaret performance
- Dance parties across the park, some featuring sing-alongs
Tickets are available now for all 4 events. For more information about offerings, pricing, and other general questions, check out the official page here.