Actually my wallet is getting more interesting as time goes on:

1 Texas drivers license
1 Maine drivers license
1 German Universitätsausweis
1 German Gesundheitskarte
1 DB BahnCard 25
1 Commerzbank VISA
4 Commerzbank EC-Karten
2 Bank of America Credit Cards (1 VISA and 1 MC)
6 Subway/Public Transport Cards (Boston, NYC, MTL, Stockholm, Western Sweden (Göteborg), Oslo)
5 EUR
500 DKK
32 USD
my American birth certificate
my American SS card
a Guteschein form a German Autobahn toilet worth €0.50
an IKEA receipt for 2700 DKK (about 500USD)
and various restaurant business cards so I can make reservations when I travel to certain cities (Dublin, Paris, Tuscany, Frankfurt, pottery in Hungary, art studio in Hungary, etc...)