San Diego is a GREAT theatre town, so after you do the Zoo/Balboa Park, check out the great shows as Old Globe, San Diego Repertory, Cygnet, or La Jolla Playhouse and tons of smaller theatres! checkout www.sdwhatsplaying.com for current shows and links to tickets (some half-price!).
Also, North Park has become a great neighborhood for food, drinks, and music (start at 30th & Upas). Some favorites include Sea Rocket Bistro (local sea food and veggies and beer), Ritual Tavern, Toronado, The Linkery, and Urban Solace.