I have a Mars Pathfinder Stamp autographed by Astronaut James Lovell (Apollo 13).
It's 1 of 5000, so there are a lot of them out there, but I love it.
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“All his life he tried to be a good person. Many times, however, he failed.
For after all, he was only human. He wasn't a dog.”
― Charles M. Schultz
Warning: The above post may be dripping in sarcasm and full of smartassedness.