This is one of my favorite 'trippy' tunes. Like 'Big Empty', it begins relatively sedate and builds up and pulls back again, etc. Likely you've heard this already, but if not, you really owe it to yourself to find it in better quality than mp3. Then, using a decent set of cans, slap them babies on your noggin, kick it up a few notches and hold on to your skull.
Pink Floyd - One of These Days - YouTube