My own 6.5 year-old really enjoyed her first Shakespeare - A Midsummer Night's Dream.
Like many topics we end up learning about, we stumbled unto Shakespeare haphazardly. She read some quotes on the back of a smoothie packet for one.
I finally found Mr William Shakespeare's Plays by Marcia Williams.
Set out with a simple rendition of the story, a smattering of the actual play's dialogue, and surrounded by spectators to reinforce the fact that they were/are plays to be experienced as an audience. The illustrations are lovely and the audience's feedback is amusing for children.
I also found her an Usborne version. It always helps to read or see a story over different versions or media. I haven't found an animation I like yet - that would be fab. I found a few but the first is a little dark and serious for her age. We watched the short and sweet BBC tale.
Although the story centres around two couples in love with the wrong people, children pick up on the mischief of the puck and the general mayhem.
She wanted to read further from the first book but I don't think the rest are quite interesting enough for her age. We did try The Tempest and I was right - didn't intrigue her half as much. We might leave it another year before introducing more, but she now has a foundation.
One day out of the blue she asked me to 'annoy' her. When I performed the mock annoyance she exclaimed...
"I charge thee, hence, and do not haunt me thus"