"as far as events are concerned, we're done with this semester"
can you replace it with "Let's call it a semester" or "Let's wrap up for the semester"? Other suggestions?
The semester has drawn to a close, time to party.
As of now this semester is but a thing of the past, lost for ever in the ubiquitous, eternal space-time continuum, now nothing more than a whisper in time.
Your second two (Let's call it a semester, and let's wrap up) are better than the original because it's too wordy and "As far as events are concerned" isn't a normal thing to say.
The semester's over.
The semester's done. (That's not really proper, but it's common).
The semester's finished.