It's summer where I live, and one of my favorite things to do when the weather's nice is to take my laptop outside to the deck where I sit in my zero-gravity chair and write--but NOT anything I plan to publish. I use the environment as a prompt. I write "willy-nilly," meaning I simply start writing without concentrating on all of the things I normally care about when preparing something for publication. It helps my brain "let off steam" and relieves the pressures of daily life.
Sometimes I close my eyes and take in all the sounds and smells. I feel the breeze and the sunshine and begin to type my reactions to all of those things. Sometimes I watch a bird and type about what it's doing. Sometimes I hear power equipment in the background and imagine what is going on, or I hear motorcycles or four-wheelers on the two-tracks that meander through the woods around my home, and I type my own fantasies about riding them where no one else exists at that precise moment.
When I finish typing, I make it a point to read what I've written without using an editor's eye. Instead, I hide what I have invented within one of the folders on the memory cards of my brain; often, I use that invention another time. Sometimes I simply highlight it all and press "delete." No one even knows that I've been a spur-of-the-moment author, but I know that I have made an attempt at being creative, letting my thoughts guide my fingers on the keyboard. There is no better feeling than letting loose all of the pent-up words that have been filling my head. It's a great way to allow them to overflow by trickling rather than flooding.
Give it a try.