At our school, we do a family reading night. We use Monarch books - which are chosen by the Illinois Library Association - but any set of books would work. The teachers and librarian share the responsibility of making sure students are familiar with these books by the time Family Reading Night occurs. Then, parents bring their entire families to tihs night put on by teachers, administrators and the librarian. There are activities centered around each book, such as science experiments, food to go with it, readers theater, etc.
These are all ways for parents to get involved wth their child at home. If parents and students can reread a book and recreate a Family Reading Night Project that they love, family literacy is occuring. If students and parents get the idea to turn their own books into readers theater scripts together, family literacy is occuring.
In fact, a Reader's Theater night would be a fantastic way to encourage parents to read aloud to kids. Showing parents how to model expression and expect it out of their children as well, in a way that makes reading fun and involves the whole family, is priceless.
A school wide event incorporating technology would be incredibly useful as well. Many parents have tablets and kindles, and many students are reading books to on these devices. Teaching parents how to find worthwhile apps, how to use the tablet to best read aloud with their kids, how to record and playback the books that they read, are all ways that technology could be incorporated into encouraging parent read-alouds.
One thing that I do in my classroom that parents and students alike LOVE is Mystery Reader. Every Friday a parent comes in and reads a book that they have chosen to the class. This gets kids to see parents as readers and as lovers of books. If they love reading enough to come in and share it with the class, then it must be important and great! Students also get to hear multiple adults reading with fluency and expression, and their get to hear how books sound different when different people read them. (For example, if a parent reads a book I have previously read, or I read one they read, we can discuss how it sounds different when each person reads it). This gets parents involved and makes them feel like they are a part of their student's literacy learning.