Absolutely go to Tijuana.

While not as exotic as travelling to Mexico City, it certainly will be an interesting evening. Lots of souvenir and trinket shops. The main drag in Tijuana is Avenida Revolución, easily walkable from the U.S. border

Do not drive across the border as it can be excruciatingly slow coming back into the U.S. Better to park at the border. Exit Interstate 5 at the last exit (San Ysidro). There is plenty of parking at the border, and walk across. There is also a high-end outlet mall at the San Ysidro exit (on the US side).

You'll find walking back to the U.S. in the evening to be pretty fast. Most Mexicans cross into the U.S. in the daytime, so all you're left with are the gringos crossing back.

There are some excellent restaurants in Tijuana. Here's a New York Times feature on one of my favorite restaurants Misión 19.

http://www.nytimes.com/2011/03/09/di...pagewanted=all

Anthony Bourdain recently did a write-up on his favorite Tijuana restaruants...

http://www.utsandiego.com/news/2012/...rants-and-bar/

Go, and have fun.