How about "Talking With........"  Eleven woman's monologues you can split among three, four or even five different directors.  Also, either of the Neil Simon "Suite" plays.  Three acts with three different stories.  What about David Ives' "All in the Timing"?  Six one-acts in one evening.  Peter Shaffer has two one-acts, "The White Liars" and "Black Comedy".  There are usually performed in an evening.  There's a start for you. 

At a former theatre, we did an evening of one-acts every year; it was kind of understood that the newest would-be directors would do a one-act first.

I was in an absolutely great one-act years ago called Pvt. Wars.  Three Vietnam vets in a mental hospital; it's funny and moving.  It's better than the expanded full-length version of the same title.

I recommended the Suites on another thread, and I second Tristan's Williams recommendation.  David Ives has tons of good ones, not just the ones in All In The Timing.  Do some poking around in the catalogs; there's a lot of good stuff out there.

Although we found, when we did evenings of one-acts years ago, that it wasn't terribly popular with our audiences (small crowds), it is a terrific idea for letting new directors, producers, actors, etc., get their collective feet wet.  That's how I got started directing 28 years ago. It is a really good idea to assign an experienced director, producer, tech person, etc., to work with each of the new people and kind of guide and teach them.

As for suggestions, I concur with the posters above.  All great plays.  Might also want to look around for plays written by local playwrights and give them a chance to "get their feet wet" too!  Perhaps contact your local arts council or your state community theatre org., if you have one, and ask if they know of any home-grown writing talent.

This year we tried some ten minute plays and the response was overwhelming. 

It started as a way to encourage local writers to write for the stage.  We felt that it would be asking too much to ask first time playwrights to do a full play so we settled on the ten minute format.  We got a couple of the Actors Theatre of Louisville ten minute play anthologies from Samuel French and studied the genre. 

Our local response was far more than we ever anticipated.  We worked with each playwright to polish their plays then did full productions of eight of them in an evening.  We were very flexible in the format of the submissions - the idea was to encourage the writers - some of the submissions were very simple - just an idea and we worked with the writer to make a play out of it.  Other submissions were very polished.  While we accepted submissions from out of town playwrights, they were informed that their material would be used only if we did not get enough local participations.  Many of the first time playwrights have written several more plays and some are moving to longer formats - one acts and full length plays.

It was so successful that we did two more batches of them. 

The audiences love them (if you don't like what you are seeing, something else will come along in a few minutes), the actors loved them (eight rehearsals instead of 35 and everyone gets a good role) and the playwrights liked the short format.  While the actors only have eight rehearsals (plus a tech and dress where we put all eight plays together for the first time), the director ends up with 70 two hour rehearsals over four weeks!!!  We ended up splitting the work load.  Luckily many of the actors could rehearse during the day.

In 2007 we will add the genre of one page plays to be read during the set changes between the ten minute plays.  The playwrights gave us unlimited right to produce their plays for 12 months and we gave them a DVD of the performance of their play.