On Monday night, SpaceX will try the "most difficult start ever" of the Falcon Heavy its first night launch of the ship, which will transport several satellites into orbit.
Also on board is the Lightsail 2, a crowd-funded awning test mission currently being advertised by Bill Nye. The spaceship will be the first to be powered solely by sunlight. The Japanese spaceship Ikaros previously used awning, but Lightsail will be the first to use solar technology exclusively. I'll let Bill explain it:
In addition, the Falcon Heavy will launch a Deep Space Atomic Clock that may or may not be used to direct future spaceships to distant targets.
If You Want Take a look at all the action, you have to stay up late. The launch of the Falcon Heavy is expected to take place at 23:30 ET / 20:30 PT. A livestream of the event will be available on the NASA website and on the You Tube channel (embedded below).
If You Miss It In addition, you can get a record of the event later this week on NASA's YouTube channel.