My mom has this fast and firm rule that works everytime...
Start peeling potatoes! :D
It's uncanny, but whenever I'm stumped about what to fix for supper, I follow this rule and start peeling potatoes. Within a few minutes I remember the frozen italian sausage in the freezer, and then the recipe just kind of floats out of the air and into my brain... Some caramelized onions, sliced up sausage, a bit of wine... hmmm. Some mashed potatoes with that. hmmm... Some shaved carrots? Yeah. Carrots with a bit of maple syrup (the real stuff please)...
And there you go. Before you're finished peeling potatoes, you have the entire meal planned out, where 5 minutes earlier you had no clue what could find it's way to the table for supper.