In the left column you'll find various page listings with different databases to help you in your research. Also, note the sword-wielding librarian as well - he's also armed with knowledge (and puns) and can help you find materials and give your research direction!
Finding plays in print form can be a little tricky - the big problem is that a script is literature, and all literature is grouped together (novels, short stories, poetry, essays, criticism, etc). That's fine if you want to find all of a single author's work together and you're looking for that author. It's a bit more problematic if you want to browse a number of scripts all together.
If you know the name of the playwright, enter that in Search It and that will take you to plays and collections by that playwright - for instance - Neil Simon:
If you don't know a playwright, however, it can be a bit trickier. One useful method is to seek out collections of plays by various authors. Here's a few examples to get you started: