One of my favorite hacks for getting into a productive mindset is putting on Bitches Brew by Miles Davis.  The album has a frenetic, chaotic, energy which pumps me up and keeps me focused.  It's great for any type of work but it's perfect for brainstorm sessions.

The songs are highly unstructured and full of dissonant sounds; they're incredibly interesting and enjoyable.  There are no lyrics to distract me (I rarely work to music with lyrics) and high BPMs keep me energetic.

I'll often mix it up with other jazz or occasionally electronica...  What works for you?

Here's the title track from Bitches Brew: