What might make a good surprise for the forum community is to finally unveil these long-awaited emails/PM from Satoshi that Theymos said will only be made public in several years 
I like the collectible coin idea but I can wait for this, I can't for the emails. Come on Theymos! 2013 + 8 years = 2019
And to post the hidden comments from Satoshi, I'm sure there are some.
I'll probably release Satoshi's PMs and logged IPs addresses in ~8 years. This'd probably be of great historical interest. (Though he always used Tor, as far as I can tell.)
I like the collectible coin idea but I can wait for this, I can't for the emails. Come on Theymos! 2013 + 8 years = 2019
And to post the hidden comments from Satoshi, I'm sure there are some.