Lemme see... The full list of stuff I got:
-Caution Pirates Sign
-Inflatable Krawk Island
-BugEye McGee Action Figure
-Governors Mansion Stamp
It would appear that the prizes have been glitchtacular though so I dunno what all everybody is supposed to get. They say on the neoboards that the theme and stamp are for "day and date". I did all challenges the day they were released and didn't miss a day, so I guess that's what does it?
though, i'm sure i did all the challenges the day they were released as well.