As a former Bakersfieldian, I feel your pain. Other than what you've listed, about the only thing to do in Bakersfield is hit the mall, which ain't what it used to be.
I like dez40's suggestions of driving over to the beach (MUCH cooler and where I escaped to from Bakersfield) and/or the Paso Robles wine country (Still hot, but much prettier area compared to B-town).
The Kern River Canyon is a pleasant drive up to the communities of Lake Isabella & Kernville and would make for a nice day trip. Just don't let the inviting waters of the Kern River lure you in. That river is treacherous..... looks calm on the surface, but the undertow is strong and can pull a person under very quickly.
Edited: 9:20 am, July 09, 2012