The Big Bang Theory season 7, episode 21 airs tonight on CBS! Here’s a new clip, and everything you need to know about “The Anything Can Happen Recurrence.”

Sheldon’s implacable intransigence may suffer an interruption tonight, when The Big Bang Theory season 7, episode 21 airs tonight on CBS. The episode, titled “The Anything Can Happen Recurrence,” will focus on Leonard’s attempts to inspire his lanky roommate by instituting unfamiliar changes into Sheldon’s routine.

According to the official synopsis for The Big Bang Theory season 7, episode 21, Leonard’s insistence that “anything can happen” leads to other unexpected results.

When Sheldon tries to be spontaneous, it leads to unexpected friction between Penny, Amy and Bernadette. Meanwhile, Raj seeks Howard’s help in preparing for a date with Emily.

Last time on The Big Bang Theory, Sheldon found himself forced to break up with string theory in the light of new scientific developments. While Penny tried to help a desolate Sheldon through the breakup, Howard found himself in the awkward position of having left Raj’s new girlfriend Emily with a very distinct memory of a previous meeting. Sheldon also may have permanently severed his ties to Stephen Hawking, but that remains to be seen.

The preview for “The Anything Can Happen Recurrence” focuses on Sheldon, as he continues to grapple with the empty hole left by string theory – and tries to fill it with frightening new experiences.

In a sneak peek from The Big Bang Theory season 7, episode 21, Sheldon tries to find his passion, and the idea for “Anything Can Happen Thursday” makes its return.

Still photos from “The Anything Can Happen Recurrence” offer a peek at the future, as Sheldon strikes forth into new experiences. The pictures also hint at what Howard, Bernadette, and Amy will be up to this week as well.

The Big Bang Theory season 7, episode 21, “The Anything Can Happen Recurrence,” will air tonight at 8:00 p.m. on CBS.

What do you think will happen when anything can happen?