Ensenada, Mexico
Ensenada is an alright place. There's not a lot of stuff to do there, but it can be somewhat relaxing, and it attracts a lot of college students from California who otherwise wouldn't be able to drink. It is about a two hour drive south from Tijuana, but seems much safer, and more hassle-free.
Most of Ensenada is a lot like other Mexican cities. The tourist area near the waterfront is quite nice, and there are plenty of cheap restaurants and crappy souvenir stores to spend time in.
There are a couple of museums in town. There's a small one that is built into an old jail, and there's this one that is part of some sort of historical site that doubles as a reception hall for weddings.
The marina area has a nice park and boardwalk to walk around. Ensenada is popular with cruise ships and is a nice place to spend a couple days if you are heading down that way.