We always used to pop the unopened purple flowers of, I think, some kind of hosta. And my grandparents showed me how to use bladder campion (Silene vulgaris) as a kind of popper by picking off a flower by the fine stem, gathering up the edges of the blossom's open end between your thumb and first two fingers so that it becomes like a little balloon (or, well, bladder...) and then popping it against the back of your other hand. This is amusing for the kind of person who likes popping bubble-wrap (me, for example), though I'll admit to having some qualms about the thoughtless destruction of life for mindless fun. In the U.S. it's alien and considered invasive; do remember to check on the population status of wild plants before playing with them.
Sinsull, we stuck the maple things on our noses too, and my dad always called them Pinocchi-oaks, as in the long nose of Pinocchio (we knew they weren't oaks, but the tree reference/word-play was okay with us!).
Cheers, Margaret