I am one small little piece of paper, yet sometimes hold lots of value. I am all you need to get in to big events, but will cost you. I am an important part of travel. And if lost, you're not coming. What am I?
Answer: A ticket.
This riddle appears in the following downloadable PDF files:
Can you solve one of the most famous logic puzzle ever?
Memory Matching game for kids, adults and seniors.
Connect the matching tiles and pop them all.