In the Dorfman Theatre there's The Red Lion - Marber's account of modern masculinity laid bare in an old-fashioned football club.  The much larger Olivier is home to what he calls a 'fiddled about with' version of George Farquhar's 1707 classic comedy The Beaux' Stratagem.
And in the Lyttelton there's a new version of Turgenev's 1870s Russian classic usually known as A Month in the Country but now re-titled Three Days in the Country.
No writer has previously filled all three auditoriums on the same night.  Only the 225-seat Temporary Theatre has evaded Marber's clutches.  "But it's just the way the scheduling worked out," he says.  "No one really planned it this way".  But it's proof that a long fallow period for the playwright has ended.
In the mid-1990s he was the hottest young writer in London theatre.  There were big hits at the National - and on Broadway - such as Dealer's Choice (1995) and Closer (1997).  Closer was made into a film by Mike Nichols starring Julia Roberts and Jude Law.
But until this year Marber, now 50, hadn't come up with an entirely new stage-play for a decade.  He says the reason was simple.
"I couldn't think of one.  I tried and I abandoned various plays.  I got half way there sometimes, or a quarter of the way there.  But a play is something you have to live with for a very long time.  You've got to love the thing and I just didn't manage it."
The Red Lion is a tragedy about football, which I suggest to him may be a wholly new genre.  "Not if you're an Arsenal fan.  But I don't think the play wholly is a tragedy: it has laughs too."
It's not the first of Marber's works to address the nature of modern masculinity.  Many of his characters appear intimate with despair.  I ask him if there's a line from The Red Lion back to Turgenev  - a profoundly sad story which has gorgeously comic moments too.
"Yes I think it's true that there is a link.  There is an underlying tragedy in both plays.  But in Three Days, for instance, our brilliant cast gets real comedy out of the situations Turgenev created."
Critics have praised the way performers such as Mark Gatiss, John Simm and Debra Gillett (who's married to Marber) extract both humour and sadness from his reworked version of the Russian original.
"All these three projects were very different.  I loved being back in Farquhar's comic world - it was a play I did as a student and I loved it then.  But with Three Days I'm also director: it's a thrill to have the intimacy of working with great actors and to know you can still work on the script in rehearsal."
We discuss which playwright is most likely to match or even exceed his schedule-domination at the National.  I suggest the prolific Richard Bean may one day come snapping at his heals.
"Oh there's any number of writers with more vim and energy than me.  I expect someone will emerge from the shadows."
Marber can be forgiven for having made a quiet tour of the three auditoriums on Wednesday night as each of the three plays entertained their audience.  I joined him in the hidden-away director's box at the back of the Lyttelton stalls for part of Three Days in the Country.
"It's a wonderfully private place to sit.  You can study the audience reactions, even if it's from behind.  You can't see faces but it's lethally obvious if anyone nods off."
That seemed unlikely as the audience fell about at the comic scene in which Dr Shpigelsky (Mark Gatiss) offers himself in marriage to Lizaveta (Debra Gillett).  "It's all in the original Turgenev," insists Marber.  "I just souped up the comedy a bit."
Yet when later Lizaveta gives her response, the spectre of tragedy looms in the play once more and the audience isn't laughing.
Patrick Marber is reluctant to talk much about his next project.  Perhaps in the past decade too many plans got stuck half way.  He says only that it's a screenplay about a married couple.
"But what I really want is to write more plays.  That's where I feel I belong - in the theatre.  I didn't do enough of it in the first half of my career and now it's what I want to concentrate on.   I just want to be a bit more productive."
Patrick Marber insists it's coincidence that for two consecutive nights this week the National Theatre is a relentless 'Marber-thon'.