Irvine itself is suburby, but nearby Newport Beach, Laguna Beach, and Huntington Beach are all fun beach towns with lots of restaurants, piers, sand, and proper downtowns. I see people playing disc golf in Huntington Beach central park.
Irvine does have the Spectrum outdoor mall, which I thought was kinda cool coming from crappy Michigan malls. Irvine also has Blizzard headquarters which gives tours...not sure if you'd be able to sign up in time but it's there if interested.
One restaurant that's kinda cool is Yard House, there's one in Irvine at the Spectrum. The food is good but not spectacular, American modern stuff, however there's like 100 beers on tap, so it's cool to go sit at the bar and see all the taps.