Ever heard of Napoleon Hill? How about his book, Think and Grow Rich? In the book, the basically tells the secret to obtaining wealth (well, no secret really, it's in the title of the book) and also shares his passion for Coke and talks about his son biting a radio and also explains how he used to have imaginary council meetings every night for a few years with his "invisible counselors".
He sounds quite the weird dude, to say the least. And I have to admit, there were a lot of goofy stuff in the book. But once you see through the fluff and find the good parts, you're in for a treat.
My absolute favourite of Hill's ideas is the one already mentioned above:
Choose a set of people the judgement of whom you admire or whom you admire in general or who you think could challenge your thinking in some way. They can be alive or dead, real or imaginary, but you should be familiar with their ideologies and opinions. Close your eyes and imagine a meeting room of your choosing with a table and chairs for all the people, including you, to sit. Have the people come in and sit down. Watch what happens.
When you start doing this exercise for the first time, it might be a good idea to ask the council a question you want an answer to or a philosophical dilemma to ponder. Since you know what kind of people they are, your subconscious will make them behave accordingly. Some will talk more than others. Some will have a lot of ideas. Some will speak only occasionally, but everything they say is pure gold. Some might try to establish themselves as the leader. Some may try to pick a fight. And some might be late every time.
A word of warning: this exercise might be very uncomfortable at times. I once tried having a one-on-one session with Ayn Rand. She just sat there, smoking a cigarette, looking at me as if I wasn't worth her time. (I wasn't, of course.)
Getting the people to behave in such a way that you don't constantly think it's just your mind controlling them might take time but once you make it work, the council meeting offers an interesting and lateral way of solving problems and getting new and fresh ideas and perspectives. Because there's no limit what you can have them talk about. And who knows, since the whole event is just the product of your imagination, you might find out something new and exciting about yourself as well.