The invitation to Stephen Hawking’s time travel party, which was held with the hope that someone from the future would make the effort to come back in to time to attend it.
On 28 June 2009, Hawking held the party, releasing the invitations after the party was held. Unfortunately, no time travelers showed up. “”I gave a party for time-travellers, but I didn’t send out the invitations until after the party. I sat there a long time, but no one came.”