based on experiences of people who visited us:
South Coast Plaza (for shoppers)
In-n-out Buger from people who haven't tried (i.e. east coasters)
the beach (choose from many options - Newport pier, Laguna, San Clemente pier, etc)
Laguna Canyon/ Crystal Cove parks for nature lovers
Local eateries (not of the fancy variety, just local joints like Slaters 50/50 or Mama D's or the numerous options in old town Orange)
hmmm... that's about all I can think of right now... oh yeah, and over priced homes in Irvine!!!