Sometimes I get inspired to improvise with a little puff pastry. In general, puff pastry is pretty forgiving; it's filled with butter, so even if something gets kind of messy or screwed up, it's guaranteed to taste good.
You could make this type of appetizer with any number of ingredients, sweet or savory. For this particular improv, I chopped and sauteed about a cup of mushrooms, then chopped around a 1/4 cup of kalamata olives, and maybe an ounce of gruyere cheese. I only used one sheet of puff pastry, but the second time I made this I just doubled everything and made a larger batch.
Here are some photos of the process I used to create little puff pastry envelopes. If you pinch the dough together slightly, it sticks to itself. Then I brushed the tops with olive oil and threw them in the oven at 350 F for about 17 minutes.
The timing suggestion and temperature were in the directions for an apple galette on the inside of the box. The important thing is to get them golden brown (frak! I have no picture of them when they're done! Sorry!).
Other possible fillings: any kind of sauteed veggie, such as asparagus, with a small amount of cheese; berries and cream cheese; even bananas, peanut butter, and chocolate chips sound good to me (if extremely fatty). I think they're kind of adaptable to whatever you need. If cheese or dairy aren't your thing, just leave them out and have the mushroom and kalamata version, which is plenty flavorful on its own (or ditch the olives for something else you like). They're fairly easy to put together and they end up looking kind of fancy-schmancy.
Note: I recently read in Vegan Brunch that the Pepperidge Farm brand of puff pastry is vegan (which is sort of suspicious, but useful).
Have you ever improv'd an appetizer like this? If so, I'd love to hear about it!