I went to Austyn Psych Fest in 2014 and king gizzard played their epic “head on/pill. I’d never heard of them before and it had a big impact on me. This is the most psychedelic song in my mind.
http://youtu.be/Rm4Hx6xCwDwThere’s a 3 minute buildup and then they go berserk. Skip to 3:35 if you’re in a hurry.
Another good one is The Amboy Dukes - Journey to the center of the mind (with a young Ted Nugent killing it on lead):
http://youtu.be/TokYdNmOt3s